Code: Mutation
by Kittenclysm
Summary: When the supercomputer gets switched back on, the TMNT team heads to France to discover the secrets of the virtual world and run into the only six teens that understand it and the evil AI that lives within it.
1. Dreams

**A/N: Hello, everyone! This is Kittenclysm, coming to you with my third fanfiction, Code: Mutation. If you read about this in one of my other fanfictions, you already know that this is a crossover of Nickelodeon's Teenage Mutant Ninja Turtles in 2012 and Code: Lyoko before Evolution. I'm only doing this before Evolution because I can't find an English dub of that anywhere. By the way, when I imagined this story, I thought that they would all be a year ahead, Jeremie and Aelita would be together and Yumi and Ulrich are together.**

 **Just for my own promotional reasons, my other crossovers are Of Gems and Mutants (2012 TMNT/Steven Universe) and Miraculous Guardians (W.I.T.C.H./Miraculous, Tales of Ladybug and Cat Noir.) A lot of the chapters of those fanfictions will say that they were written by LatinButterfly20, but that was my username before I changed it to Kittenclysm. But please check them out if you want. Anyway, let's get on with the story!**

 **Disclaimer: I don't own Teenage Mutant Ninja Turtles or Code: Lyoko.**

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Chapter 1)Dreams

Aelita ran behind her father outside as he ordered her. He blocked the back door with a plank of wood that lying in the grass.

Franz opened a door that was hidden behind some weeds that Aelita had never noticed. "Follow me," he said. When he entered, however, Aelita instantly lost sight of him, as if he had just walked into the abyss. "Daddy!" the young girl cried.

She tried following, but was stopped when three men in black suits stepped out from where Franz Hopper had vanished.

She gasped and turned around to run, only to see that more men had broken the wooden plank and starting to surround her.

She saw an opening between two men and slipped through them.

She quickly ran back into her house, planning on running out the front door.

She gasped when she saw four Kankrelats, blocking her only escape.

Aelita ran up the stairs as the mechanical monsters fired lasers at her. She turned around and saw both the Kankrelats and men in black following her.

She ran into her room and locked the door behind her.

She turned around and noticed a computer she had never seen before.

On the screen was a weird symbol that looked strangely like an eye.

She approached it as she heard banging on the bedroom door. A familiar woman appeared on the computer, surprising the young girl.

"Mommy?"

" _Aelita, help us_ ," her mother said in a distorted voice. It sounded as if a man was talking along with her.

"Mommy!" Aelita screamed, grabbing the screen.

" _Aelita, help us_ ," she repeated. "'Us'? What do you mean 'us'?"

The screen shut off and a bang from the bedroom door drew her attention away from the computer.

She turned around and was mortified to see the door's hinges were breaking and about to fall off.

Aelita cowered in fear as the door finally broke down and the monsters and men piled into her room.

The last thing she remembered was the sound of lasers being fired and her own screams.

+=0=+

Aelita screamed as she jolted upright in her bed. She rubbed her eyes and looked around her room.

She sighed in relief as she realized that the entire thing was just a dream, and she was in her school dorm.

She grabbed her cell phone, getting ready to text Jeremie about her nightmare, until she saw the clock.

2:30

She realized it was too early in the morning and that he wouldn't be awake for another three and a half hours.

So, she decided to leave him be and try to get some more sleep.

She closed her eyes and tried to sleep, but her mother's distorted voice kept ringing in her mind, keeping her up.

+=0=+

"No way."

"Yuh-huh."

"No, Odd."

"Yeah, Ulrich."

The two boys were having another disagreement, like the others.

They carried their breakfast trays to their normal table where the rest of their group sits.

"Jeremie, will you talk some sense into him?" Ulrich said to the blond genius. "Alright," Jeremie said with a sigh, "What is it now?"

Kolossus vs Mega tanks," Odd told him. "Well, that's a good one," Jeremie said, "How many tanks?"

"Ten," Odd said, "I say that if they position themselves just right, they'd be able to take him down!"

"And I say that there is no possible way!" Ulrich said, "The Kolossus has too much protection. The Mega tanks wouldn't be able to break that, let alone beat it!"

Yumi and William came up to the boys, carrying their trays.

"Hey, guys," Yumi greeted. She noticed the glare between Odd and Ulrich and instantly knew what was going on, "Okay, what is it this time?"

"Kolossus vs ten Mega-tanks," Jeremie informed them. "Oh, totally Mega-tanks," William said. "Thank you!" Odd exclaimed, getting a few students' attention.

"I doubt it," Yumi said, "It took four towers to control the Kolossus, but the Mega-tanks could control themselves. It has too much power."

"What do you think, Einstein?" Odd asked."That's pretty hard to figure out," Jeremie replied. "Too bad we can't turn the supercomputer back on," William said. "He thought for a minute, then said, "Wait, can we?"

"No, William," Jeremie said, "It's too dangerous."

"How? We killed X.A.N.A., remember?" Yumi said. "I don't know. I just have a bad feeling," Jeremie told them. "Well, how about we ask the queen of Lyoko?" William said, noticing the pink-haired teen coming up to them with her own tray.

She slowly sat down and rested her head in one of her hands, using the other to take small bites.

"Hey, Aelita, you think you can settle an argument between me and Ulrich?" Odd asked her. "Mmm," she moaned tiredly, barely paying any attention to the conversation.

"Well, I keep telling Ulrich that ten Mega-tanks could've taken down the Kolossus, but he seems to think…" Odd's voice faded out as Aelita started to think about her dream.

" _Aelita, help us_." The words kept ringing in her mind, not letting any other thought in her head.

"Aelita? Aelita," Jeremie said, nudging his girlfriend back to reality. "Huh?" She looked at the five people, looking at her in confusion.

Aelita, are you okay?" Ulrich asked. "Uh, yeah, just a little tired," Aelita answered.

"Well, we have classes this morning,do you think you can make it to the end of the day?" Jeremie asked. "Yeah, I think so," Aelita said with a yawn.

"Hey, Stones!"

They turned and saw Sissi, Herb, and Nicholas, coming over to them, the leader wearing an angry expression.

"Who do you think you are?" she said.

"Hey, lay off, Sissi," William said, "She had a rough night."

"Yeah, well, thanks to her, Sissi lost 90 minutes of sleep last night," Herb defended, "And if she doesn't get her full nine and a half hours, she can't think straight in class."

"Are you kidding? If her thoughts got any more curved, they'd be going in circles!" Ulrich joked, making his friends laugh.

Sissi growled and stormed off, the two boys following.

The gang looked over at Aelita again, only to see her fast asleep.

When they saw students start to throw away their trash and leave, Yumi nudged the sleeping girl, "Aelita, it's time to wake up, class is starting in a few minutes."

Instead of waking up immediately, she mumbled something about her father and men in black suits.

Aelita!" Odd shouted, nudging her harder. "What?" she asked. "Classes are about to start," William said. "Oh," she simply said. She grabbed her books and threw away her uneaten food.

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After what felt like a week-long day, Aelita trudged back to her room.

She threw her books and papers on her desk and dropped on her bed, almost instantly falling asleep.

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 **A/N: I hope you enjoyed this chapter. If you did, please read and review. I would also really appreciate it if you shared it with friends and whoever you think would like it. Also, I'm am completely open to any suggestions you have and I'll try to fit into the story. Anyway, thanks so much and I'll see you in the next chapter, MEOW!**

 **-Kittenclysm**


	2. Restart

**A/N: Welcome, my kitties, to the second chapter of Code: Mutation. I'd like to thank Cpt. Leo and Blue Tagg for being my first followers. I am actually so excited for this story and so happy there are people who want to see more of it. Let's go!**

 **Disclaimer: I don't own either of these shows, but I wish they would bring them back.**

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Chapter 2)Restart

Aelita opened her eyes and found herself in a Lyoko tower. She automatically felt confused, she knew she was in her school room. She decided to exit and look around.

She followed the platform out and found herself in the forest sector.

"Jeremie?" she asked, expecting to get a reply, but was met with silence.

She decided to explore and walked around, until she ended up at the edge of the sector.

Suddenly, the teleporter shot out of the digital sea and scooped her up. Within seconds, she was in Sector 5.

Except when she was released, she wasn't in the normal drop-off, but the terminal in the dome. She walked up to the screen at the edge. She touched it and what came up on the screen gave her chills.

 **HELP US!**

She gasped and stepped back.

" _Aelita_ ," she heard someone say. She looked up and saw her mother, appearing to be shackled to the wall of the dome.

"Mom?" Aelita said.

" _Help us_ ," her mother said, once again, sounding as if a man was talking alongside her. She remained confused at the plea that she begged her. Until she saw a white orb emerge from under the platform. She instantly knew what it was, "Dad?"

The orb floated over to her mother, who clung it to her chest and they both disappeared into the wall.

"No!" Aelita reached out, trying to catch them, but it was too late. They were gone.

Aelita dropped on her knees and started weeping.

Her cries were interrupted by a growl. She turned around and saw three Creepers coming toward her. The only thing she could think to do was to jump off the edge, so that's what she did.

+=0=+

Aelita sat up in her bed. Once again, she pulled out her phone and looked at the time.

00:15

She thought about her dream and knew what she had to do.

She threw on her clothes and headed to the factory.

+=0=+

An alarm on the computer started to go off, waking up the sleeping blond.

Jeremie stumbled to his desk, blindly searching for his glasses.

When he finally found them, he put them on and started working on the computer.

"What?" he said to himself. He typed away on the computer, "Someone turned the supercomputer back on?" He pressed a few buttons and found the only person in the virtual world. He threw on his headset and tried to talk to her,

"Aelita, what are you doing in Lyoko?"

When she didn't reply, he check the connection, suddenly realizing that she cut off communications. He grunted and threw on his clothes.

He left his room and headed for the old building.

+=0=+

 _New York City 6:30 p.m._

The seven teens laid around the lair, doing different recreational things.

April, Mikey, and Casey were watching tv, Donnie was working in his small lab, Raph was playing on the arcade game, and Karai and Leo were practicing their fighting.

They were all startled when the computer started to blare a loud alert.

"Donnie! Turn that stupid computer off!" Raph yelled, covering his ears.

The scientist turtle ran over and shut off the alert. "No, this can't be right," Donnie said, typing on his computer. "What was that about?" Leo asked, he and the others coming over. "About a year ago, I found a strange, unexplainable disturbance somewhere in France," Donnie explained, "I started to keep track of the activities, but a few months ago, it just...stopped. I completely forgot about it, but it seems as if it's started up again."

"How are you able to keep track of something that's in a country that's across the Atlantic Ocean?" April asked. "I've found connections to it through a backdoor hack in the internet."

"Isn't that illegal?" Leo asked. "Not when you do it incognito," Donnie said, continuing to type, "Whoa!"

"What is it?" Raph asked, feeding a couple of celery stems to Chompy. "I just got an email," his brother answered. "From who?" Casey asked. "I don't know," Donnie said. He clicked it and began to read it aloud,

" _You don't know who I am, but I have been watching your virtual activity for a few months now, and have viewed you through different resources around your city: street cameras, security devices, even this computer. That may seem to be very invasive, but I wanted to be sure you and your friends can be trusted to help us. We need you to travel to France, near Kadic Academy. You will find six people who can help you in our rescue. I have already hacked into the school's system and applied for April, Casey, and Karai to go, so the school will bring you here. I will send you the information I entered when you get to France. Please, you ninjas are the only ones that can help free us._ "

"That's creepy to think that this guy's been spying on us!" Mikey said. "Donnie, can you track him?" Leo asked. Donnie checked on the screen, "He's an even better hacker than I am," he answered, "He somehow scrambled his IP address. I have no idea where this email came from."

"Think we should help him?" Karai asked aloud. "Well, it's not like there's much to do here since Shredder's gone," April said with a shrug, "At least we'll probably get some kind of adventure."

"Sounds like a good enough reason to me," Casey said. April's phone rang and she pulled it out. She put it on speaker so everyone could hear, "Hey, dad."

" _Can someone there explain to me why I just got an acceptance email from a boarding school in France?_ "

"Yeah. Donnie just got an email from someone over there, saying that they need our help."

" _You're not actually thinking about going over there, are you? What if it's a trap?_ "

"Dad, you don't understand, they need our help."

"You don't have to worry, Mr. O'Neil, she can protect herself and we'll be there, too," Donnie said, "Besides, if they don't go, the school's going to wonder what happened to them."

Kirby sighed in defeat, " _I guess there's no choice._ _Alright, you can go._ "

"Yes! Thanks, Dad!" April said. She hung up her phone and put it back in her pocket, "Well, I guess we should pack."

"Okay, let's get ready," Karai said. "Actually, Karai, I think we need to get you a new look," April said. "What?" Karai said, "Why?"

"Well, you're going to normal school," April answered, "And this whole...assassin look...might be kind of intimidating to normal kids."

"Alright," Karai said, slightly annoyed, "Let's go." The three teens headed toward the exit. "We'll bring her back in a while," April said, "See you later, guys."

They left the lair, leaving the turtles alone. "Maybe we should let everyone know that we're leaving," Leo said, "Donnie, call everyone here."

+=0=+

In less than an hour, the Mighty Mutanimals, Mona Lisa, Bebop and Rocksteady were all gathered in the turtles' small home.

"Yo, man, why'd you get all of us here?" Bebop asked, slightly annoyed. "We called you all here to let you know that we're going to be leaving for France in a few days," Leo explained, "What?" Mondo Gecko asked, "What for?"

"Someone contacted us and told us that they need our help," Donnie said. "Who?" Mona Lisa asked. "We're not sure," Raph said, "He didn't leave a name and Donnie can't track him."

"He scrambled his IP address, so I can't even figure out where he sent the message from," Donnie said, "But we think that's he's stuck somewhere with someone else."

"Anyway, we need you guys to watch the city until we come back," Leo told them.

"Do you know how long you'll be gone?" Mona Lisa asked, going up to Raph. "Hopefully not long, but we're not sure," Leo answered, "We'll let you know after we get more information from this guy."

"We're back!" April called as she entered with Karai. April entered first, but then turned around when she saw that the other girl was staying in the other part of the lair, "Come on, Karai."

"No, it's embarrassing," the snake-girl said. "It's not embarrassing, it's just different," April said, "Come on."

Karai slowly stepped into the room and everyone's mouths hung open, completely surprise by her new appearance.

She had on a red, short-sleeved shirt, with a black, broken heart on the front, along with a knee-length black skirt that cut halfway up her thigh, and a pair of black boots with red soles that stopped just above her ankles. Her hair was now down and pulled back in a low ponytail.

"One laugh and someone gets bitten," she threatened. "No, Karai, you look good," Mikey said. "Okay, I guess it'll have to do," she said.

+=0=+

 _Factory 1:00_

The chair moved around the holomap of the virtual world, bringing the computer up to the young genius. He put his headset on and typed a few keys, "Aelita?" Once again, he realized that Aelita disconnected the communication function so that it was only accessible from Lyoko.

The elevator door opened a few minutes later, with Odd, Ulrich, and William coming out, all looking exhausted. "Jeremie, why did you call us here in the middle of the night?" Odd asked, rubbing his eyes. "Yeah, and why is the supercomputer back on? I thought you said it was too dangerous," William said.

"It is! I didn't turn it back on," Jeremie said, "Aelita did. She turned it back on and sent herself to Sector 5."

"Why'd she do that?" Ulrich asked. "I don't know," Jeremie said, "She cut off communications from her side. I can't talk to her," Jeremie said, "I need you guys to go back to Lyoko and find out what she's doing."

"Well, we'll probably be a little rusty, but I think we can handle that," William said. "Good," Jeremie said, "Did you get a hold of Yumi?"

"Yeah. She said she'll have to sneak out, but she'll get here," Ulrich said. "Okay, head down to the scanners."

The boys did as ordered and got back in the elevator and pressed the button to go down.

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 **A/N: If I remember right, near the end of the TMNT series, Bebop and Rocksteady beccame good guys. And I hope you like Karai's makeover. Remember to read, review and share and to throw any ideas and I can try to throw them in. See you in the next chapter. MEOW!**

 **-Kittenclysm**


	3. Starting Over

**A/N: Hello, my kitties! And welcome back to Code Mutation. I'd like to welcome my newest follower, Michael78, who joined right as I was reviewing this chapter. And a comment to my reader Matt, the reasons it takes me so long to update sometimes is because I'm working on another fanfiction. Also, I don't think I've mentioned to anyone on this website, but I've had multiple brain surgeries to remove a brain tumor and I'm prone to seizures. So it's hard for me to focus and forgetful sometimes and I lose interest in things very easily. So you just have to please be patient with me. But let's get going.**

 **Disclaimer: I don't own TMNT or Code Lyoko**

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Chapter 3)Starting Over

The elevator opened, with the Japanese girl stepping out into the lab. "Jeremie, what's going on?" Yumi asked. "Aelita sent herself to Lyoko and we can't get a hold of her," Jeremie explained, "The guys are down in the scanner room. You ready to go back?"

Yumi nodded and got back in the elevator and pressed the button.

+=0=+

"Man, I never thought we'd ever see these things again," Odd said, looking at the reactivated scanners.

" _All you really need to do is get there and get Aelita to reenable the communications_ ," Jeremie told them through the speaker, " _I can't talk to you until she turns it back on._ "

"Got it," William said, "It'll be nice to go back to Lyoko and _not_ be under X.A.N.A.'s control."

"Just don't try to be a hero this time," Ulrich laughed. William gave him a sarcastic laugh, "Got it."

Ulrich and William were the first two to go into the scanners.

The scanner doors slammed shut as Jeremie began the transfer,

" _Transfer, Ulrich. Transfer William. Scanner. Virtualization_."

When the doors opened, the boys were gone.

"Ready to go?" Odd asked Yumi. She answered with a nod and they stepped into the same machines.

+=0=+

Yumi and Odd landed on their feet and found themselves in the dropoff of Sector 5, along with Ulrich and William, who had his large Zweihänder behind his head. "Welcome back," Ulrich said.

The wall spun until the door finally opened and the four ran through it.

Within a few minutes, they made it to the terminal, where they found Aelita, with her full attention on the screen in front of her. "Aelita!" Yumi said. The young girl wasn't fazed by the call. "Aelita, answer us," Odd said, "What's going on?"

Once again, Aelita said nothing.

Jeremie sat and stared at the screen, until three enemy symbols came on screen. "What!?" Jeremie said to himself. He hit keys on the computer and found three Creepers, heading toward the five Lyoko warriors.

Jeremie wanted to wanted to let them know, but he saw the communications were still disabled. "How am I going to warn them?"

He then remembered something and began the old program that he created.

Tired of Aelita ignoring them, Yumi stepped up to her and turned her around, "Aelita, what are you doing here?"

"I don't have time," Aelita said. She turned back around and continued to work. "Aelita," Ulrich said.

Suddenly, the Overwing, Overbike, and Overboard all virtualized to their sides.

"Something's wrong," Yumi said. "Aelita, turn the communications back on. I think Jeremie's trying to tell us something," William said.

Aelita moved her hands on the screen and reactivated the function.

" _Guys, there's Creepers coming after you!_ " they heard Jeremie's voice say. "What?" Ulrich said.

They heard multiple growls and the sound of the monsters crawling toward them.

All except Aelita, who was still on the screen, turned around in time to see one of the three Creepers fire a laser.

They jumped onto the vehicles and the laser hit Aelita in the back.

She finally turned around and nearly froze.

When she saw the Creepers charging at her, she flashbacked to her dream. She remembered jumping over the edge. She hesitated when she looked over at the void of blue.

" _Aelita, what're you doing?_ " Jeremie asked as he saw her icon on the screen move closer to the end of the platform. She closed her eyes and fell off. "No!" they all yelled. Odd was quick and fired one of his laser arrows at her. She devirtualized before she could hit the dome and they all sighed.

"Okay, you can bring us back now, Jeremie," Odd said. Within a minute, they all disappeared from the virtual world.

+=0=+

"Aelita, what are you thinking, starting up the supercomputer?" Jeremie asked. They were all gathered back in the lab. "You don't understand, Jeremie," Aelita said. "What?" Ulrich said. "I...I think my father is still alive," Aelita admitted. "Aelita," Jeremie said. He wrapped his arms around her to comfort her. "Aelita, you remember. Your father had to sacrifice himself so we could defeat X.A.N.A.," Ulrich said solemnly. "No, I know he's still out there!" Aelita said. She released herself from Jeremie's hold and went to the computer.

"What really disturbs me is the Creepers," Yumi said. "What do you mean?" William asked. "I mean, I think someone is controlling them," Yumi replied, "Why else would they be active?"

"Well, I guess we can leave the supercomputer on while I run a scan, but if we don't find anything, then we shut it off again," Jeremie said. He walked over to the computer and began a scan.

Then, he let out a yawn, "Come on, we better get back to bed."

"Yeah, I should get back home, too," Yumi said, "I'll see you in the morning."

They left the factory and Yumi went back home, while the others went back to the dorms.

+=0=+

Aelita poked at her breakfast with a frown on her face. "Aelita, we're sorry," Ulrich said, "But you know that there was almost no possible way that he was still alive."

Aelita dropped her utensil, "No! I know that he's still out there!"

"Aelita, if Franz Hopper was still alive, Jeremie would have let us know by now," Odd said. "Sorry, Aelita," Yumi said, placing her hand on her friend's back as she put her hands over her face.

"Guys, you won't believe what I found!" Jeremie said, running up to them with his laptop in his hand. "What?" William asked. Jeremie put the computer on the table and turned it to them, showing what looked like a moving line graph with multiple spikes. "Unbelievable," Aelita said. "Uh, Jeremie, I know I spent months in a computer, but that doesn't mean I know how to read this kind of stuff," William said.

"Well, you remember how I ran that scan on the supercomputer the rest of the night?" Jeremie said, "Well, at some point here," he pointed to the first spike in the graph, I recorded some sort of unusual activity in the internet."

Meaning?" Ulrich asked. "Well, this is unusual because it wasn't caused by any person, but a form of artificial intelligence," Jeremie explained. He hit a few keys on the laptop and a second graph, similar to the first, popped up.

"What's that one?" Yumi asked. "Well, I was curious, so I went and checked some of the old records I kept from some time ago," Jeremie explained, "This second graph is the activity that occurred while X.A.N.A. was still active. You see how they're identical?"

"Wait, are you telling us that…" Odd said. "Yes," the blond replied, "X.A.N.A.'s back."

"Hey, Stones, Belpois," Sissi said. She walked up to the group, "My father wants to see you two in his office after breakfast."

"Why us?" Aelita asked.

"How should I know? Just go to his office and find out for yourself."

She simply walked away after this, leaving them all in wonder.

+=0=+

The two geniuses sat in the chairs sitting outside their principal's office. "Ms. Weber, do you know what Mr. Delmas wants us for?" Jeremie asked. "I'm sorry, Jeremie, but I'm not allowed to give you any information without the principal's permission," the secretary said, not looking away from the computer on her desk.

Aelita noticed Jeremie let out a shaky breath. "It's okay, Jeremie, I'm sure it's nothing serious," she told him.

"That's not what I'm worried about."

"X.A.N.A.?" she whispered. He looked at her and nodded. "Don't worry about that either," she said, "We'll figure it out."

" _Nicolette, you can send them in now_ ," they heard Mr. Delmas say over the speaker on her phone. "Yes, sir," she answered back, "You can go in."

They opened the door and stepped inside.

+=0=+

"So what did the principal want to see you about?" Ulrich asked as they all sat at their table in the cafeteria. "Apparently, we're getting a couple new students tomorrow night, and he wanted to let us know that they're going to be our roommates," Jeremie said. "I think it'll be nice, but Jeremie told me he doesn't want one," Aelita said. "Why not?" Odd said. "It's not that," Jeremie said, "If I have a roommate, it'll be near impossible to keep the factory, Lyoko and X.A.N.A. a secret."

"It'll be tough, but we can get through it," Ulrich said."Who are the new students?" Yumi asked. "Uh, my roommate is Casey Jones," Jeremie said, looking at the paper in his hand, "Apparently, he's on the school's hockey team in New York."

"What about yours?" William asked Aelita. She looked down at hers, "I'm getting two, April O'Neil, who went to school with Casey, and Karai Tatsumi, who was homeschooled her whole life."

"Tatsumi?" Yumi said, "I'm pretty sure that's Japanese."

"Well, I hope they're not like Sissi," Ulrich said. "I'm sure there's no one out there like Sissi," Yumi laughed and the others joined her.

+=0=+

Karai put her new clothes in the suitcase that April was nice enough to let her use for their trip.

She packed another one of her black skirts, and then picked up the photo of Tang Shen and Splinter when he was human. She sat down on her makeshift bed and looked at it sadly, thinking of her late parents. She wiped a small tear forming in her eye.

"Hey."

She looked at the doorway and saw Leo, leaning on the wall with his arms crossed and a worried look on his face. "What?" she asked standing up. "What's wrong?" her younger brother asked. "Uh, nothing," she said, carefully putting the picture in the suitcase. "You miss them," he said simply. Karai looked to the side and sighed, "Yeah."

"Well, that's okay," Leo said, "We all do."

"I just wish I knew Splinter as long as you guys did."

"Well, you just have to remember, he pretty much knew _you_ his entire life," Leo said, "And he always held you in his heart." He passed her the picture of her parents with her infant self.

"Thanks, Leo," Karai said with a smile. "You should finish packing," Leo said, "Your plane leaves tonight."

+=0=+

 **A/N: Thanks for reading! Remember to leave reviews and share and throw me ideas and I'll try to put them in. Also, do you think I should keep spelling the name X.A.N.A. or should I switch it to XANA? Let me know in the reviews. See you in the next chapter. MEOW!**

 **-Kittenclysm**


	4. Welcome to Kadic

**A/N: Hello, my kitties! Welcome back to Code: Mutation! I'd like to welcome my newest followers, Michael78 and Jonathan Thomas Crist. Thanks for joining and I hope you like the story! Let's go!**

 **Disclaimer: I don't own Code Lyoko or TMNT**

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Chapter 4)Welcome to Kadic

"So, what do you think these new students will be like?" Ulrich asked Odd. "Don't know," his roommate replied. They were currently in Mrs. Hertz science class, whispering to each other. "It doesn't matter to me," Jeremie said, leaning behind himself to talk to them, "As long as this Casey guy doesn't disturb me while I'm working on a new way to defeat X.A.N.A., he can be however he wants."

"Oh, you don't need to be so harsh, Jeremie," Odd said

"Okay, class, settle down," Mr. Delmas said to everyone, making the room quiet, "I'd like to introduce the new student joining us today."

Standing next to him was a young, dark-haired boy with a giant gap in his teeth, "This is Casey Jones. A transfer student from New York City in America."

Casey just stood and waved at them all. "Casey, you can take your seat right next to Jeremie there," Mrs. Hertz said as the principal left the room. Casey sat down next to the blond and stuck out his hand, "Hey, Casey Jones."

"Jeremie Belpois," he replied, shaking his hand. "Hey, you're my new roommate, right?" Casey asked. "Yeah," Jeremie said, writing a few notes in his notebook, "But just so you know, I like my privacy. So, don't bother me when I'm working."

"Geez, okay," Casey said defensively. "Hey, it's okay," Odd said, tapping Casey on the shoulder, "He may seem a little cold, but you should see him around his girlfriend." Ulrich and Odd started to laugh as Jeremie growled lightly.

+=0=+

After being introduced to the math class, Karai and April sat down on opposites sides of Aelita, who was looking through her textbook. "Hey, you're April and Karai?" Aelita asked them. "That's us," April said. "Who are you?" Karai asked. "Aelita Stones," she replied, "Your roommate."

"Oh, that little toy in the room is yours?" Karai asked. "Yeah, that's Mister Pück. My dad gave it to me when I was little," Aelita said. Her eyes drifted down to her desk, thinking of her father."Hey, are you okay, Aelita?" April asked her. "Yeah, yeah, I'm fine," Aelita sighed. She stayed silent as they continued with the math class.

+=0=+

Karai and April carried their lunch trays, looking for a place to sit. "Well, that was...long and boring," Karai said. "Just give it some time, Karai," April said, "You'll get used to it."

"Hey, guys, over here!" Casey called from an open table. The two girls went over and sat down next to him. "So, how's your day going so far?" he asked. "I don't really care for it," Karai said. "That's because it's the only time you've ever been to school. Trust me, you'll fall into a rhythm," Casey told her.

They heard a girl clear her throat behind them. They turned around and saw a dark-haired girl looking at them with her arms crossed. Behind her stood a dark-haired boy with glasses, holding two lunch trays and a boy with messy, dirty-blond hair, holding one. "Can we help you?" Karai asked. "Yeah, you can get out of our seats," the girl said. "Excuse me?" Karai scoffed. "You heard her," the dark-haired boy said, "Get lost." Karai stood up and looked the boy in the eye. "You wanna say that again?"

"You heard him, go find your own table," the blond said.

Karai stared at them angrily and April quickly stood up, "Karai, it'd be better if we just found another place to eat."

Karai grabbed her tray and the three walked away, while the girl and boys took their place.

"Who the heck does she think she is?" Karai said. "That's a school bully, Karai," Casey said. "But don't worry," April said, "If you can stand up to the Super Shredder, dealing with people like her will be a breeze."

"Okay," Karai laughed, "So, where are we going to sit now?"

"Hey, April, Karai!" Aelita called as she ran up to them, "Hey, you guys looking for a seat? We got three more at our table."

"Okay, sure," Karai said. They followed the pink-haired girl to her table of friends, where three boys sat, two of which Casey knew. "Jeremie, Odd," Casey greeted. "Hey, Casey!" The boy with pointed blond hair said. Across from him was another blond with glasses and sitting two seats away from him was a dark-haired boy. Aelita sat down between the two boys and kissed the blond on his cheek. "Oh, this is your girlfriend, Jeremie?" Casey asked. "You know them?" April asked. "Yeah, Jeremie's my new roommate," Casey said, "And this is one of his friends, Odd."

"Yeah, and I'm William," the third boy said. Karai sat down next to William and Casey sat next to her, while April sat down a couple seats away from Odd. "Hey, where's Ulrich?" Aelita asked. "Running late," Odd said with a mouthful of food. "Who's Ulrich?" Karai asked. "My roommate," Odd said, swallowing so he could talk clearer, "Oh, here he comes."

Karai, April and Casey looked over to see a brunette boy walking up to the table with an older, Japanese girl with short, black hair alongside him. "Hey, guys," the girl said, she and the boy, Ulrich, sitting down, with Ulrich sitting next to Odd and Yumi sitting between Ulrich and April, "What's up?"

"Just meeting our newest students," William said. "Yeah, this is Casey Jones, April O'Neil and Karai Tatsumi," Aelita introduced. "Nice to meet you," the girl greeted, "Yumi."

"So, where were you two?" Jeremie asked. "Probably making out in the boiler room," Odd teased, leaning toward Ulrich. Ulrich just shoved his roommate, pushing him out of his chair, making everyone at their table laugh.

Odd instantly stood back up and looked at Ulrich, "That's gonna cost you one roll!" He quickly snatched the roll off of Ulrich's tray and threw it into his mouth. "I swear, Odd, one of these days, your stomach is going to eat itself," Aelita joked, "But really, where were you?"

"Looking for Johnny and Hiroki," Ulrich said. "Oh, boy," Jeremie said, pushing up his glasses, "What did they do this time?"

"Hid my diary somewhere in the school," Yumi answered. "Let me guess, Hiroki is your little brother?" Karai said. "Yeah, you got one?" Yumi asked. "Four," Karai said. "Geez," William said. "It's not so bad," Karai explained, "Only two of them is still a little immature. One a little more than the other."

"And I take it you had a run in with Sissi?" Ulrich said. "That brat over there with those two boys following her like lost puppies?" Casey asked. "Yeah, that's Sissi Delmas," Jeremie said. "She thinks she's the most popular girl in the school because her dad is the principal, but those boys are the only two that actually like her," Odd told them.

They suddenly heard a couple boys giggling somewhere behind April. She, Yumi and Ulrich turned around and saw two younger boys, hiding under the table next to theirs. "Hiroki!" Yumi shouted. She lunged at them, but they got out and ran away from the older girl, "I'm gonna get you!"

Yumi quickly caught up to one of the boys and held him by the collar of his shirt, "Okay, Johnny, where is it?"

"I-in the science building. Second floor boys' bathroom, second stall, hidden behind the toilet!" the young boy said. She let go of him without another word and the boy fled.

She came back to the table and sat down. "Well, that was...interesting," Casey said. "Yeah," she said, "Hey, Ulrich, do you mind…"

"I'll get it later."

"Thanks."

"You're pretty quick on your feet, Yumi," Karai said, "Have you ever thought about training to be a kunoichi?

"A what-a-quiche?" Odd asked, obviously confused. "A _kunoichi_ ," Yumi said, "A female ninja. Me and Ulrich practice our karate in the gym in our free time."

"That's cool," April said. "Yeah, we'll have to take Casey there so we can teach him a few things," Karai said. This made her and April laugh.

"You know how to fight?" Ulrich asked the girls. "Yeah, we're expert ninjas," April said, "Karai has been training her entire life and I've been training for a few years, but I'm a fast learner."

"Casey on the other hand, is still in training," Karai giggled.

"Well, it looks like it's almost time for class," Aelita said, noticing kids throwing away their trash. "Okay, let's get this over with," Karai sighed, picking up her tray and red bag.

+=0=+

Donnie typed on the computer, checking for the next email from the mystery person, while the others set up their new home.

His phone started ringing and he turned on the video chat. "Hey, Karai," he said. " _Donnie, have you heard anything from this guy yet?_ " she asked irritably. Donnie could now see that she was lying in bed in her dorm. "Nothing yet," Donnie said, "How are you liking school so far?"

" _Ugh, it stinks_ ," his reptile sister replied.

"What, you haven't made any new friends?"

"Actually, we met our roommates' friends and they're really nice."

"So, what's the problem?"

" _There's these three mean students_ ," she said, " _I can stand up to them. But, today, this boy got me so angry...that I almost shifted and bit him!_ "

"Well, when I find something out, I'll let you know."

" _Okay_ ," Karai said. There was a muffled voice heard on her side of the line in the hallway, " _Oh, shoot, that's Aelita. I gotta go._ "

"Okay, talk to you later," Donnie said.

They hung up together just as Aelita walked through the door, talking on her phone, "Well, did you try a DNA code scanner?" It appeared that she hadn't noticed that Karai was in the room, considering that her bed was on the backside of the door, so she kept talking to the person on the other end of the phone, "Well, you should probably try that. I know he's still out there! We have to find him!"

She closed the door and let out a small yelp as soon as she saw Karai. "I-I'll talk to you later," she said into the phone. She hung it up and put her hands behind her back. "Karai! I thought you'd be down in the rec room with everyone else!" she said. "No, there wasn't much I wanted to do down there, since Sissi took over the tv and Herb and Nicholas took the foosball table," she answered, "Who were you talking to?"

"Oh, just Jeremie."

"What were you talking about?"

"Just a computer program he's working on."

"Oh, yeah? What does it have to do with a DNA code scanner?"

"Uh…" Aelita was silent as Karai could tell that she was trying to think of something to say. "I-it's a program to determine a person's entire heritage through a single strand of hair," she said. "Cool," Karai said, not actually believing the young girl.

The door opened again and April walked in, "Hey, guys, what's up?"

"Not much," Aelita said. "Hey, Aelita, do you know where Jeremie is? Casey said that he hasn't seen him since school ended," April said. "Uh, no, I haven't seen him," Aelita said, not looking April in the eyes. "I saw him heading into the woods with the others right after classes got out," Karai told April. "I wonder where they went," April said. "I'm sure it's nowhere important," Aelita laughed nervously.

"Alright," April said, "Hey, Karai, you wanna go spar a little?"

"Finally, something to do around here," Karai said, getting off the bed and stretching.

As soon as they left the room, Aelita pulled her phone out and dialed her boyfriend's number.

+=0=+

 **A/N:Thanks for reading. I know nothing much happened, but I promise that something will happen in the next chapter. Remember to throw me your ideas and share this with your friends and I'll see you in the next chapter! MEOW!**

 **-Kittenclysm**


	5. Attacked

**A/N:Hello, my kitties! Welcome back to Code Mutation! Just like in my other fanfiction, I'd love to introduce my newest follower, Javimagine236. I love writing this story. As I promised, there is going to be some action in this chapter. I don't have anything else to say, so let's go!**

 **Disclaimer:I don't own Code Lyoko or TMNT**

+=0=+

Chapter 5)Attacked

Aelita pressed the button on her phone to turn the alarm off.

At this point, she's gotten used to waking up this early. But her roommates weren't.

"Aelita, why do you have your alarm set for 5:00 in the morning?" Karai groaned. "Trust me, if you want to beat the traffic, you need to get up early," the pink-haired girl told her. "Traffic?" April asked her confused. "You'll see," Aelita told her, grabbing some clothes and towels, "I'm gonna go shower and then hang out with the guys."

April and Karai simply lied back down. "Okay, we'll see you later," Karai said tiredly.

+=0=+

About two hours later, Karai and April left their room with their own clothes and towels and found a line of girls, leading to the bathroom. "Why is there a line?" April asked a younger, redhead girl, wearing a pink robe. "Sissi," the girl answered. "She always hogs the bathroom in the morning," said a black girl standing in front of the other girl, seemingly the same age, "And the rest of us have to wait until she's done."

The bathroom door opened and the principal's daughter stepped out. "Looks like it's going to be a long time for you two," she said, passing by April and Karai, "Guess I won't see you at breakfast." She laughed and walked towards the end of the hall.

"In that case, I'm going back to bed until the line shortens," Karai said, heading back to the room, "It's Sunday and I'm going to take advantage of the free time."

"Okay," April said.

+=0=+

It was about 45 minutes until it was April's turn to get into the shower. At this point, she was the last one and she had the entire bathroom to herself.

She took a quick shower and got out. She quickly dried herself off and put on her clothes. She then walked over to the sinks and place her T-phone that she got from the turtles onto the counter. She pulled a hairbrush out of the bag she brought in with her and began brushing through her hair.

She closed her eyes and started to hum a soft tune. She didn't notice the black aura that came out of the outlet with a hair dryer plugged into it.

She screamed as she felt the aura wrap around her and a strange, eye-shaped symbol flashed in her mind, just before she lost consciousness.

The scream was heard through the hall and inside the dorm that the three girls shared.

Karai shot up out of her sleep and looked at the door, "April?"

She ran out into the hall and saw a few girls coming out of their rooms as well.

Karai was first to get to the bathroom, while the other girls crowded behind her. She opened the door and found April, passed out on the floor. Karai saw April's T-phone sitting on the counter and grabbed it before anyone saw it.

With almost no effort, Karai picked her up and headed toward the school infirmary.

+=0=+

April felt a cold cloth on her head and a bright light through her eyelids as she started to wake up. "April? April, can you hear me?" she heard a woman say. She finally opened her eyes and saw the school nurse, standing over her. She looked around and saw Karai, Casey, and Aelita in the room with her. "Where am I?" April asked. "You're in the infirmary," Yolanda informed her.

"Is she gonna be okay?" Aelita asked. "She's fine. I think she just suffered an electric shock while using a hair dryer plugged into a faulty outlet in the bathroom. Maintenance is looking into it," Yolanda told them. "Okay, well, as long as that's all that it was, I'm going to go back to the library," Aelita said, "I'll check on you later."

After Aelita and Yolanda left, April turned to Casey and Karai, "Guys, something strange is going on."

"What do you mean?" Casey asked. "There's no way I could've been electrocuted, I wasn't using a hair dryer. I was only brushing my hair."

"Weird," Casey said. "Plus, just before I pass out, I saw a weird symbol," she said, "It looked like…" She reached over to the table next to her and grabbed a piece of paper and a pen. She quickly drew the strange eye that she caught a glimpse of, "This."

"Really weird," Casey said.

Suddenly, April's phone let out a distorted sound that startled the three of them. "What the heck?" April said. "It's your phone," Karai said, "It's been doing that randomly for the past hour. I was about to take it to Donnie to see if he can fix it."

"Oh, okay," April said. "Here, you can use mine until yours is fixed," Karai said, handing her phone to April. "Thanks," April said. "Okay, I'm gonna run this to Donnie and then we're gonna go to the rec room," the snake-girl said. "Okay," April said. "We'll see you later," Casey said, the two of them leaving.

"Bye," April said.

+=0=+

"So, do you think you can fix it?" Karai asked her smartest brother, who was observing the phone he created. "Shouldn't be very hard, what did you say was wrong with it?" he asked, plugging it into a charger. "It just keeps making this weird sound at random times," Karai said.

As if on cue, the phone let out the same distorted noise that it had earlier. "That's weird," Mikey said after the sound subsided.

"Okay, we gotta get going, or the teachers are gonna notice we're not on campus," Casey said. "Okay, catch you later," Raph said.

Right after the two teens left, Donnie's laptop went off. He quickly got on it and opened the email that popped up. "Is it the mystery man again?" Leo asked. "No," Donnie said, "This person said that we can, 'find a clue to the answer,' if we start searching in the sewers."

"Let's go, maybe we will find something," Leo said. They decided to leave their small home and search for this clue.

As soon as they walked out, the strange symbol appeared on the T-phone and a surge of electricity went from it, through the charger and into the wall. The outlet sparked before the surge continued through another plug that led into the new Metalhead.

Metalhead jerked slightly, before he turned on, with the strange eye-like symbol flashed on the screens that served as his eyes. He created a saw with his hand and cut through the cord, tethering him to the wall.

He walked out of the lair and headed to the school.

+=0=+

Karai and Casey found their new friends, sitting at a small table in the rec room, all talking to each other.

Before they got to close, Karai could hear what they were saying, due to her mutation,

"Do you think it was an attack?" Yumi asked. "I don't think so," Aelita said, "He didn't take control."

"Plus, the super scanner didn't pick anything up," Jeremie added. Karai saw William look up at her and Casey and apparently hush the others. "Hey," he said to the two. "How's April?" Yumi asked. "Fine," Casey said, taking a seat, "They think she just got electrocuted by one of the outlets in the bathroom."

"Yeah, Mr. Delmas said that no one is allowed in the dorms until they have the wiring checked out," Odd said.

The paper that April drew on suddenly fell out of Karai's bag and onto the floor. Jeremie spotted it and quickly grabbed it.

"W-what's this?" he asked. "April drew it," Casey said, "She said that it flashed in her mind just before she blacked out."

The French students looked at each other with worried expressions.

Suddenly, Jeremie's laptop started beeping. He grabbed it and opened it. "Oh, no," he said. "What?" Karai asked suspiciously. "O-oh, nothing," he said, quickly closing his computer, "But we have to go."

The six teens all jumped up and ran out at full speed. "What was that about?" Karai asked, earning a silent shrug from Casey.

+=0=+

April laid in the bed in the school infirmary, staring at the lights, with nothing else to do. Although she insisted she was fine, Dorothy refused to let her leave without giving a few more tests.

Out of boredom, she pulled out Karai's phone and started looking through it. She unlocked the screen and saw a picture of William, apparently taken without him knowing. She looked at it in slight confusion.

She was startled by a student's screams from outside. She jumped from the bed and looked out.

Metalhead was walking through the campus and destroyed a bench that sat in the open.

April tooks Karai's phone and dialed the first number she thought of.

+=0=+

"I can't believe we searched through the sewers and all we found were a couple of skateboards and a scooter," Raph said, him and his brothers walking back into the lair, carrying the items they found.

"Yeah, Donnie, that was some helpful information," Leo said. "Me?" Donnie said, " _You_ were the one that insisted we go looking!"

Their little argument was interrupted by Donnie's phone. "Hello?" he answered. "Donnie! Can you tell me why Metalhead is attacking the school?" April asked him. "What are you talking about?" Donnie said, "Metalhead is…" He looked over where he kept the robot, but only saw a torn cord, "...Gone?"

"I'm gonna get my tessen and try to stop him," April said.

She hung up the phone and headed out the door, slipping by Dorothy, making sure she wasn't seen.

April ran up the stairs of the dorms and headed toward her room.

She peeked through the window of the door that led to the girls' floor to make sure the no one was there, but saw a couple men coming out of the bathroom. She ducked under the window when she saw one of the men look her way. "I forgot," she said to herself, "Maintenance."

She looked around to figure out what to do. She looked at the set of stairs that led up to another floor, "That might lead to the roof."

She thought for a minute then ran back downstairs.

She ran out of the building and saw kids panicking because of Metalhead attacking. She looked toward the woods near the school and saw Aelita, Jeremie, Ulrich, Odd, Yumi, and William, running into the woods. " _Where are they going?_ " she asked herself. She shook the thought and continued to what she was doing.

+=0=+

The six teens descended the ladder, leading to the sewers. Odd was the first to retrieve his skateboard, but noticed it was gone. "What?" he said, "Where's our stuff?"

"Looks like we're running," William said. They took off, not giving it a second thought.

+=0=+

Donnie accessed his computer, opening Metalhead's control program. He could see through Metalhead's camera eyes this way. He could see students at Kadic, fleeing from his creation. Metalhead turn toward a large, brown-haired man with a bandage on his face, wearing a red track suit and matching headband.

The man looked at Metalhead, holding an ax in his hands, appearing to be ready to attack him. But he ran and dropped the ax when Metalhead fired a small missle out his hand and nearly hit him, but destroyed the wall behind him.

"Donnie, stop him! Shut him down!" Leo ordered. Donnie picked up the controller for Metalhead and pressed the shutdown button, but the eye appeared on the computer screen. "What is that?" Donnie asked.

A large surge of electricity went from the computer and straight into the controller, shocking Donnie and making him pass out. "Donnie!" his brothers exclaimed.

They carried their unconscious brother to their makeshift couch. "Okay, this is starting to get out of hand," Leo said, "Mikey, you stay here with Donnie. Me and Raph are going to take care of Metalhead."

"Okay, but I see two problems," Raph said, "One, it's daylight out, and two, that place is full of people."

"Yeah, but wouldn't you rather our secret be exposed than an entire school be torn apart by the robot that _we_ created?" Leo pointed out, "Plus, if they call the cops in, they might be able to track Metalhead's controls back here and discover our lair."

"Okay, let's get this over with," Raph said. He and Leo left the lair, prepared to face the possessed machine.

+=0=+

April checked the area around her, making sure there was no one around. She knew that students were not allowed in the garden shed. She heard there were a few kids that got a few weeks detention for breaking in.

When she made sure the coast was clear, she snuck over to the shed and tried to opened it, but the lock restricted her. "Of course it's locked," she sighed to herself.

She pulled a pin out of her pocket and stuck it in the lock. She moved it around a little until the door finally opened.

She slipped in and shut the door to make sure she wasn't spotted.

She searched around, finding spray cans, paint brushes, and a few gardening tools. She kept searching until she found the rope. She snatched it and ran back to the dorms.

+=0=+

April got to the door that led to the roof and once again, picked the lock to get out.

Once she was out, she climbed onto the rooftop to the dorms.

She balanced herself on the peak of the roof and walked to the opposite end, where she knew her room was. She tied the rope to a nearby antenna and her waist and carefully lowered herself down.

When she got next to the window, she peeked in and saw Mister Pück, lying on Aelita's bed. "Got it," she said. She slid the window open and slipped in. She searched through the drawers, trying to find her weapon. The first thing she found was Karai's tantos. She grabbed those, figuring that her friend might need them to fight.

She opened the drawer under the closet and her eye was instantly drawn to a picture. It was a picture of a slightly younger Aelita, with an older man, with glasses and a mustache. She looked at it in confusion, but was snapped out of it when she heard men's voices, coming down the hall. She panicked and searched through another drawer and finally found her tessen.

April reached outside the window and grabbed the rope she left dangling. She shut the window and climbed back onto the roof to sneak out again.

+=0=+

"I guess X.A.N.A. really is back," Ulrich said, all of them in the lab. "Yep," Yumi said, "But at least we know how to handle him."

"Yeah, let's do this!" William said, punching his fist in the air in excitement. "Actually, William, I think you should go back to the school and stop that robot," Jeremie said, "Or at least stall it until we can deactivate the tower."

"What?" William asked, "Why can't Odd or Ulrich go?"

"Because you're the newest part of the team and less experienced. We can't screw up on a mission this serious," Aelita told him. "You're still a part of this team," Ulrich said. William let out a groan and said, "Fine."

He got back in the elevator and press the button. The door shut and the elevator left. "Okay, ready to face X.A.N.A. again?" Jeremie asked.

+=0=+

April made it outside and saw Metalhead looking around, as if he was searching for something. He looked at her for a second and she spotted the symbol in his eyes. April gasped when she saw this and began looking for Karai and Casey.

She spotted them, standing near the vending machines, trying to calm a few students hiding there. "Guys!" she called. "April!" Karai said. "April, what's going on?" Casey said.

"Look, I now it sounds weird, but I think whatever attacked me this morning is controlling Metalhead," April informed them. "How do you know?" Casey asked. "That symbol is in his eyes," April said.

"Uh, can we talk about this later?" Karai asked when she saw Metalhead coming toward them. "Okay, you might need these," April said, passing Karai her tantos. "All right!" Karai said. "Hey, what about me?" Casey asked, realizing that he was defenseless.

"Do what a ninja would do and improvise," April said. Casey looked around and spotted the abandoned ax, lying on the ground. He picked it up, "I guess this'll have to do." He followed the two girls to fight.

+=0=+

 **A/N: I know that this chapter was kind of long, but I was so excited to finally have X.A.N.A. make an official appearance! Anyway, you know the drill, read, review, share, and throw me ideas and I'll try to fit them in. By the way, I think I'm gonna start on the next chapter right away because I'm not very inspired to write the next chapter of Miraculous Guardians just yet. But I might just overlap writing them. See you in the next chapter. MEOW!**


	6. Discovery

**A/N: Hello, my kitties! Welcome back! I know this chapter may seem pretty early, but I decided to put my other fanfiction on hiatus until I can think of new content for it, so this story will be updating a lot more often. I'd like to welcome my newest follower, Bananarock509. I hope you enjoy the story so far and the future chapters. Let's go!**

 **Disclaimer: TMNT and Code Lyoko do NOT belong to me!**

+=0=+

Chapter 6)Discovery

April threw her tessen at Metalhead, hitting him in the head.

Metalhead turned and looked at them, the symbol flashing in his eyes. "I don't know what you are, but if you want a fight, you got it," April said threateningly.

Leo and Raph hid in one of the trees near the school, watching students run out.

Leo spotted Metalhead, cornering April, Karai and Casey, who was holding an ax. "There they are!" he said.

"Okay, leader, what's your plan?" Raph asked. "I'm thinking," his brother said.

April looked in the trees and saw the two turtles.

She motioned her eyes to signal them to distract Metalhead. Leo nodded in understanding.

Just before the turtles could jump out, they all heard a boy yell from a few yards away.

"Hey, X.A.N.A! Why don't you pick on a Lyoko warrior?"

They all turned to the voice and saw William, running toward them. "William?" Karai said. No one noticed the blush spread across her face.

The teen boy got between them and the threatening machine. "William, what are you doing?" April asked. "Don't worry, I know how to handle this guy," he replied, taking the ax from Casey. "No you don't," Leo said, he and Raph jumping out of the tree.

"Whoa!" William exclaimed. "Leo!" April, Karai, and Casey said. William looked at them surprised, "You know them?"

"Yeah, they're friends of ours," Casey told him. "Actually, they're my brothers," Karai admitted. " _These_ are your brothers?!" William said.

"Guys, where are Mikey and Donnie?" April asked. "Donnie was knocked out cold by something that possessed the computer while he was trying to deactivate Metalhead," Leo told her, "Mikey's taking care of him."

"Metalhead?" William asked, still looking between them, confused by the whole scene.

They saw Metalhead look toward the woods and then run out to them. "Where is he going?" Raph asked. William gasped as soon as he realized, "The factory."

"Factory?" April asked. "Come on!" William said, running off, "We have to stop him!"

"William! Stop!" April yelled, "You can't take Metalhead on by yourself!"

"Come on, we have to follow him!" Leo ordered. They ran after the boy and robot.

+=0=+

The five ran through the woods and stopped when they saw the ax lying in the grass, broken at the handle. "Oh, no," Leo said, picking up the two pieces. "If the ax is here, where's William?" Karai asked. "There!" April said when she spotted the boy in the middle of a small clearing.

"William!" Leo called. William jumped at the sound of the turtle's voice. "Oh, hey," he said when he saw them all running up to him. "Where's Metalhead?" Casey asked, slightly out of breath.

"You mean that robot? He went that way," he pointed down the path that led out of the woods and to the more urban part of the city. "Then what are we waiting for? We need to catch up to him," Raph said. "No, we need to get there before he does," William said, "Luckily, I know a shortcut."

He bent over and moved the manhole off the entrance to the sewers. "Through here," he said, starting to descend the ladder.

Unlike him, the others just jumped down into the sewers. "Wait, isn't this where we got those skateboards and scooter?" Raph asked. "That was you?" William asked. "Sorry," the red-masked turtle said, "If you want, we can go get them real quick."

"No time," William said, "Come on. Follow me."

They did what he said and followed him through the labyrinth of tunnels.

Partway through the run, William took out his phone and dialed a number.

It rang a few times before the blond answered. "Jeremie? How's it going over there?" William asked.

" _It's a little hard here, Ulrich and Odd are down to 20 life points each and Yumi's surrounded by Bloks. How's it going on your end?_ "

"Well, X.A.N.A. definitely took control of Metalhead."

" _Metalhead?_ "

"Yeah, I'll explain later. Anyway, he's headed to the factory and I'm worried about what he might do."

" _Okay, I'll keep an eye out for it._ "

"Okay, I'm gonna try to cut him off at the entrance. We're coming through the sewers."

" _Okay, we'll try our best here._ "

"Okay."

William hung up his phone, "Man, I wonder how X.A.N.A. created a robot like this."

"Well, this X.A.N.A. guy didn't make him," Leo said, "One of other brothers did. Metalhead's built with highly advanced alien technology."

They ran until they got to a gate in the sewer. "Oh, great, you brought us to a dead end!" Raph said. "No, I didn't," William said. He pointed above himself and they all saw a covered exit.

+=0=+

Donnie opened his eyes and looked around the lair. The only person in the room with him was Mikey, who was playing video games.

"Uh, where are Raph and Leo?" Donnie asked, walking up to his youngest brother. "Oh, they went to help the others try and stop Evil Metalhead," Mikey said. "What?" Donnie said, "You let them go to face him?"

"Well, it's nothing to worry about April, Karai, and Casey are there too," Mikey said, waving it off. "Well, I think we should help them anyway," Donnie said.

"Alright," Mikey sighed. He turned off the video game and they grabbed their weapons and left the lair.

+=0=+

William uncovered the exit and climbed out. He turned around and reached down to help Karai climb out. "Thank you," Karai said to him once she climbed out.

The others quickly climbed out behind them and were instantly surprised by the giant factory in front of them. "Keep an eye out for Metalhead," William said. He pulled out his phone again, "Jeremie? How are things going?"

" _Bad. Ulrich's been devirtualized and Odd only has a few arrows left. We're gonna need you on Lyoko._ "

"What about Metalhead?"

" _I'm sure April and her friends can handle it. And I'll send Ulrich up to help._ "

"Okay, just make sure he knows what's up here," William said. He hung up his phone and walked over to the others.

"Hey, can you guys handle yourselves for a few minutes if Metalhead shows up?" he asked. "What?" Leo asked, "Where are you going?"

"I'm going to help Jeremie and the others stop this guy," William said. "Jeremie?" April asked. "Yeah, it's this whole thing that has to do with the computer program that's controlling Metalhead," William said, "It's hard to explain. But Ulrich's gonna get up here to help you." He started into the factory, "And if Yumi and Odd come back before it's over, then they'll come and help you, too."

He ran off before they could ask anymore questions. He quickly slid down the rope and ran toward the elevator shaft.

The elevator came up just as he reached it. The door opened and Ulrich stepped out. "Okay, anything I need to know before I get out there?" he asked. "Yeah, there's these weird looking guys, but they're on our side," William told his friend. "Yeah, those human-sized turtles?" Ulrich said, "Jeremie showed me on the security cameras. Now hurry up and get to Lyoko."

They switched places, placing William in the elevator, and sending Ulrich outside with the ninjas.

+=0=+

Mikey and Donnie ran toward the school, expecting to see either Metalhead, their friends or their brothers, but only saw that the entire campus was devoid of any person, human or mutant. "Where are they?" Mikey asked. "Hang on," Donnie said, pulling out his T-phone, "I'll check."

He opened the GPS and pressed the button to pinpoint Leo's phone. "What're they doing down by the water?" he said aloud when the icon appeared on his phone, "Come on. We can get there through the woods." The two headed into the wooded area.

+=0=+

Within a few minutes, Donnie made it to the bridge leading to the old, run-down factory. "Whoa! What is this place?" Mikey said. "According to the internet, it's an old factory that use to manufacture miscellaneous machinery," Donnie said. "You mean it used to make stuff like video games and robots?" Mikey said. "Probably not, it says it was shut down and abandoned nearly 30 years ago," Donnie explained. "Oh," Mikey said, "So why would everyone come down here?"

"I have no clue."

They got closer to the factory and spotted their friends, standing in the middle of the bridge, seemingly on guard. "Guys!" Mikey yelled. "Mikey! Donnie!" April said. "Did you see Metalhead on your way here?" Leo asked. "No," Donnie said, "More importantly, why are _you_ here?"

"William led us here," Casey said. "William?" Donnie and Mikey asked. "One of our classmates," Karai said, "He was surprisingly chill about Raph and Leo."

"Guys, I'm coming!" Ulrich said, coming out of the factory. "Ulrich?" April asked. "What?" Ulrich said, stopping in his tracks as he saw the turtles, "I thought there was only two of them!"

"Are you talking about us?" Donnie asked, crossing his arms. "Uh...Yeah," Ulrich said hesitantly. He looked at Leo and instantly noticed the weapons strapped to his back, "Hey, are those _real_ katanas?"

"Yes," Leo answered, "We're trained ninjas."

"Do you think you can fight with one?"

"You know how to use them?" Leo asked. "Kind of," Ulrich said. "What do you mean, ' _kind of_?'" Raph asked.

"Here comes Metalhead!" April said before the brunette could answer the red-masked turtle. "Here," Leo said, quickly handing one of his swords to Ulrich as the others took out theirs. "Whoa, these are heavier in the real world," he said. "What?" April asked, not understanding why he would say that.

They suddenly heard metallic footsteps coming up on them quickly. Ulrich raised the sword in a way that Leo thought made him look like he knew how to use it. "Okay, Ulrich, just so you know, Metalhead is adaptive and learns," Donnie informed him. "Yeah, well, we're not dealing with Metalhead," Ulrich replied, "We're dealing with something a lot more dangerous."

"How do you know that?" Casey asked. Ulrich stayed silent as he watched the robot head toward them.

+=0=+

 **A/N: I hope you enjoyed this chapter. Remember to read, review, and share with anyone you think might also enjoy it. And any ideas you have, send them in comments or PM me and I'll try to fit them in if I can. Thanks for reading and I'll see you in the next chapter. I'll get right on it! MEOW!**

 **-Kittenclysm**


	7. Turtles vs XANA

**A/N: Hello, kitties! Welcome back. I know this is early again, but I just LOVE working on this story! I am going to start working on other fanfictions, but those won't be put online until I finish another story because I'm only going to take on two at a time. Anyway, let's get on with the story!**

 **Disclaimer: I don't own anything!**

+=0=+

Chapter 7)Turtles vs X.A.N.A.

" _Virtualization_."

William fell into the Ice Sector, falling over slightly after he hit the ground. "Okay, still gotta get used to that," he told himself.

" _Alright, I wasn't able to get you any closer, they're 23 degrees southeast of your current location_."

"Got it." He took off to help his friends.

+=0=+

Raph jumped in front of Ulrich, blocking Metalheads blade from attacking him. Donnie had noticed that Metalhead was mostly focusing his attacks on the boy.

"I don't know what you did to this X.A.N.A. guy, but he really seems to have it out for you," Raph said. "He has it out for me _and_ my friends," Ulrich told him. Karai rammed into Metalhead, knocking him a few feet away, "William and the others? Why?"

"Ulrich raised the katana again and blocked the robot's attack, "Because we're the only ones that can prevent him from destroying our world. He takes us out, there'll be no stopping him."

"Okay, and where are your friends right now?" Raph asked. "They're trying to deactivate X.A.N.A.'s attack," he replied. "Dude, that makes no sense," Mikey said. "Wait, is X.A.N.A. what attacked me this morning?" April asked. "Yeah," Ulrich said, "Sorry about that."

+=0=+

William ran to the location that Odd, Yumi and Aelita were, trying to fight off the monsters surrounding them.

He reached the scene just as a tarantula hit Yumi with a laser that took out the last of her life points and devirtualized her. "Dang it!" he said. He pulled out his Zweihänder and ran it into the monster's back, instantly turning him into nothing but code.

He held his weapon above his head in victory. "Uh, we're not out of the woods yet," Aelita said, "We still have to deactivate the tower."

"Oh, yeah. Where is it?"

"It's in the basin that's at the end of that long tunnel," she said, pointing to an opening in a cliff. "Okay, let's go," Odd said.

The three ran into the tunnel, unknown to the danger that waited on the other side.

+=0=+

Yumi ran out of the factory and, like Ulrich, was caught off guard by the sight in front of her.

There was Karai, April and Casey, along with four giant, bipedal turtles, all carrying ninja weapons. She saw Ulrich, standing with a katana in his hands, blocking an attack from the robot she saw at the school. She screamed as she ran toward them and kicked the robot away for a brief moment.

"Hey, Yumi," Ulrich greeted casually. "Hey," she said back.

"Look out!" Mikey yelled. Yumi turned around just in time to see Metalhead, coming back at her. She prepared herself for the impact and was only pushed a few feet backward, running into Ulrich and knocking them both to the ground.

The katana fell out of Ulrich's hand and slid to the edge of the bridge. "No!" Ulrich exclaimed.

April threw her hand toward the sword and used her telekinesis to prevent it from falling. She pulled it back to herself and threw it back to him, "Ulrich!" The brunette caught it with ease. "Wow," Ulrich said, noticing what she had done.

+=0=+

The three Lyoko warriors kept running until they neared the end of the ice tunnel they were in. "I can see the tower!" Aelita said, pointing to the exit.

When they were a few yards away, William stopped and put his arm in front of the other two. "What is it?" Odd asked.

"Something doesn't seem right," William replied, "It's too easy."

He stepped out in the giant, bowl-shaped area and a giant wall of ice suddenly appeared between him and the other two.

"Jeremie? What's going on?" Odd said.

"I don't know," Jeremie said, typing on the computer. He was startled when a symbol appeared on the screen, heading for William, "Oh, no! The Scyphozoa!"

The jellyfish monster picked up William and put its tentacles to his temples, attempting to take control. "It's a trap," Jeremie said. "No!" Aelita said, she and Odd hitting the ice that divided them.

Odd frantically looked around the tunnel and spotted a hole in the wall. Without a second thought, he used his claws to easily climb up the wall and into it. He had to crawl a few feet into it until he ended up in the same area as William and the Scyphozoa.

He shot a few arrows at it before it squealed, released William and fled. William put his hand to his head, "Yep, I remember _that_."

"Yeah, at least you got away this time," Odd joked. William laughed as he staggered to his feet. "Okay, so what do we do about this?" he asked, putting a hand on the ice wall.

Ulrich's phone came up on the computer and Jeremie answered.

" _Jeremie, how are things going? It's getting tougher to keep X.A.N.A. from getting in!_ "

"We're almost there. But X.A.N.A. created a wall between Aelita and the tower!"

" _Well, hurry up and try to figure something o-_ " The call was cut off after Metalhead attacked and Ulrich's phone broke when it hit the ground below the bridge.

"I can't believe I didn't remember!" Aelita said. She dropped to her knees, closed her eyes and started to sing. A giant hole opened in the ice and Aelita ran through. She ran by Odd and William and straight into the tower.

Like she used to do, she reached the center, where she was lifted to the top and entered the code. All of the panels on the wall dropped to the bottom, turning the entire inside dark and the red aura on the outside turned white.

+=0=+

Metalhead raised his circular saw attached to his hand above his head and tried to attack Karai with it.

Karai, who had twisted her ankle and was stuck on the ground, covered her face in fear, not knowing what was going to happen, while everyone watched, unable to think of anything.

She was still cowering until she heard Leo say, "Uh, Karai?"

She uncovered her face and gasped when she saw the blade a few inches away from her face and Metalhead was frozen in place. She pushed the blade away from her so that she could stand back up and Metalhead fell to his back and his screen go blank. "Is it over?" Mikey asked. "Yep," Yumi said. "So, what now?" April said, "Yeah," Karai said, trying to get back on her feet, "Do you really trust us with your secret?"

"Doesn't really matter," Yumi said. "Why not?" Raph asked. "Because in a few seconds, you won't remember any of this," Ulrich replied. "Huh?" April said.

She then noticed a giant, white dome start to grow out of the factory and consume the entire area. She closed her eyes to keep herself from going blind.

+=0=+

 **A/N: Whoo! Only took three days to write this one! Okay, I really enjoyed writing this chapter! And I hope you enjoyed reading it. I know there wasn't really too much action, but I'm not really good at that sort of writing, even though I'm more into watching action cartoons. I'm just not good at** _ **writing**_ **action. But either way, I hope you liked the chapter. You already know to read, review and share and throw me ideas. And I'll see you in the next chapter. MEOW!**

 **-Kittenclysm**


	8. Back In Time

**A/N: Hello, my kitties! Welcome back to Code Mutation. This took me a little longer because I used to use a RCA tablet with a detachable keyboard, but it got worn out and the keyboard wouldn't connect anymore, so I had to wait until I could buy a new computer. But now I got one, so I'm back in business! Anyway, let's go!**

 **And a message to Sal: I don't remember Sissi becoming friends with the gang at the end of Code Lyoko, unless it's at the end of Evolution. Please let me know.**

 **Disclaimer: I do not own either show or characters.**

Chapter 8)Back in Time

April kept her eyes closed, although, strangely, everything was dark now. Even stranger than that, she could tell that she was lying down.

Suddenly, she heard a familiar ringing sound and it suddenly go silent as she opened her eyes to the dark room.

"Aelita, why do you have your alarm set for 5:00 in the morning?" she heard Karai groan. "Trust me," Aelita said, "If you want to beat the traffic, you need to get up early."

"What?" April said, confused by the whole scene. "You'll see," the pink-haired girl said as she grabbed her clothes and towels, "I'm gonna go shower and then hang out with the guys."

"You know, I think I'll come with you," April said. She quickly jumped out of her bed and grabbed the things she needed. "O-okay," Aelita said. April could see the confusion on her face. "Okay, I'll see you later," Karai said.

Aelita and April walked to the bathroom, with a few other girls leaving their rooms as well and walking with them.

"They like to beat Sissi to the showers too?" April asked her roommate. "H-how did you know about that?" Aelita asked. "I heard it from someone," the red-head replied.

+=0=+

April and Aelita both came out of the bathroom at the same time and Aelita started for the exit. "Hey," April said, "Where are you going?"

"I told you, I'm going to go hang out with the guys."

"You mind if I come with you?" April asked. "Uh, actually, we're working on a complicated computer project, you probably wouldn't be interested in it," Aelita said. April could tell she was lying, but didn't press it any further, "Okay, I guess I'll just see you at breakfast?"

"We'll see you there."

April went back to their shared room, where Karai was already back asleep.

"Karai, wake up," she said. "What?" Karai moaned, sitting up and rubbing her eyes, "What do you want?"

"Karai, how did we get here?"

"Uh, we took a plane," the snake-girl replied.

"No, I mean, how did we get back to the dorms?"

"What do you mean 'back to?' This was our first night here.'"

"No, we were just at a huge fac-. Wait," April said, a thought suddenly crossing her mind, "How does your ankle feel?"

"It feels fine," Karai said, "What's up with you?"

April stayed silent for a minute, then said, "Nothing. I'm gonna do a little reading until Casey gets up."

"Okay, sure," Karai said, lying back down. April went to the desk they all shared and turned on the lamp, pulling out a book and opening it up.

+=0=+

"It's weird," Aelita said to her friends, "April didn't do the same thing that she did last time. Last time, she just went back to sleep, but this time, she came to the bathrooom with me." She and the boys were sitting at the table, discussing the events that occured a short time ago.

"That _is_ weird," Odd said. "What's so weird about that?" William asked. "When we use the return to the past, anyone that isn't scanned into the supercomputer just do the same thing that they did before the jump back in time," Jeremie said.

"And what about those weird turtle guys?" Ulrich said. "What weird turtle guys?" Odd asked. "Oh, yeah, you never came out of the computer," William said, "There were four turtes that were the size of people. They wore masks and carried ninja weapons. It was so cool!"

"Oh, man! I wish I could've seen them!" Odd pouted. "It's okay, Odd," Wiiliam said, jokingly putting his hand on his friend's back, "We'll probably see them again."

"Why's that?" Aelita said. "Karai told me that they're her brothers," William told them. "Are you serious?" Ulrich said, "I seriously never thought that my life could get this weird."

"Hey, guys," April said, coming up to them with Casey by her and they sat down, "What're you talking about?"

"Oh, nothing," Aelita said, slightly startled by them. "Where's Karai?" William asked. "She decided to sleep in, so I'm gonna save her some breakfast," April replied. "Hey, Odd, Ulrich, can I ask you something?" Casey asked. "What's up?" Ulrich said. "Well, I was coming out of our room and I swear I heard a dog barking in yours," he said. "Oh, it's nothing," Odd said, waving it off.

"So, what are you doing today?" April asked them. "Oh, nothing," Jeremie said. "Like I told you, we're just working on a computer program," Aelita said. "Oh, well, one of Karai's brothers is a computer genius," April said, "I can call him and he can probably help you work on it."

"No, it's okay. We can figure it out ourselves," Odd said. "Really?" April deadpanned. "Yeah, in fact, we better get going to the...uh...electronics store in town...to get some more programing equipment," Jeremie said, "Come on, guys." The five of them picked up their empty trays and threw it out and left the cafeteria.

"Okay, hurry up and eat, Casey," April said.

"What? Why?"

"Something's going on around here. It's like the day started over and no one remembers anything."

"What the heck are you talking about?"

"A few hours ago, we were at a giant factory with the others and the turtles, fighting off Metalhead, who was possessed by someone named X.A.N.A."

"No," Casey said, "A few hours ago, we were asleep," He took a bite of his toast and a drink of juice, "It was probably a dream."

"Trust me, it wasn't. There's a factory down by the water and there's something inside that they don't want anyone to know about."

+=0=+

After they were done at the cafeteria, they went back to the boys' dorms.

"I don't know what you're expecting to find," Casey said, unlocking the door to his and Jeremie's room. Anything that has to do with X.A.N.A. and this factory," April replied.

"Okay...and what is a X.A.N.A.?"

"It's a person or a thing that wants to take over the world."

They walked into the room and looked around a little. April spotted the computer on the opposite side of the room, "Hey, what's on the computer there?"

"Don't know. Jeremie doesn't let me get near it. Says there's too much of his work on it and he doesn't want me to ruin it."

April groaned a little and pressed a key on the keyboard to turn on the screen. She tried to access one of the folders, which was labeled JOURNAL on it, but was met with a password block, "He obviously doesn't want anyone to see what's on there," Casey said.

"Well, I'm not giving up that easily," April said, pulling out her phone. She dialed Donnie's number.

" _Hey, April_ ," the genius answered. "Donnie, I need your help," April said, "Me and Casey are trying to see something on his roommate's computer, but it has a password lock on it. I need your help to hack it."

" _Okay, plug your T-phone into the USB of his computer_." April did as she was told, "Okay, it's done."

" _Okay, give me one minute_."

The two could hear him typing on his computer.

After a minute, Jeremie's computer beeped and the document opened on its own. "You did it, Donnie!" she said.

" _Okay, if that's all you need, I'm gonna get back to my work_."

"Okay, talk to you later." She hung up the phone and started to search through the files on his computer. "Check this out," she said, "Not only does Jeremie and the others have something to do with X.A.N.A., but he has a whole bunch of entries that date back to three years ago."

She closed the folder and opened another that was labeled FRANZ HOPPER DIARY.

Once it was opened, she scrolled through a few entries and noticed the complex computer programs and codes in almost every one, "Man, this Franz Hopper guy knows a lot about computers." She kept going until she reached the final entry, "That's weird."

"What?" Casey asked. "Whoever he is, his last entry was created more than ten years ago," she replied. "Well?" Casey said, "What does it say?"

April went back to the beginning of the document and began reading, " _This is it! The virtualization program is completed! Soon, my daugter and I will be able to travel into the computer and try to locate Anthea. I can't let anybody discover X.A.N.A. or the supercomputer, or all my years of hard work will be for nothing. I do have a failsafe if X.A.N.A. does try anything. The two of us will be the Guardians of Lyoko and deactivate any attack that X.A.N.A. launches. I hope this will work._

"See, I told you! X.A.N.A. is real!" she said after she closed the file. "Okay, but who is Franz Hopper?" Casey asked, "And how is he related to all of this?"

"I don't know. But Donnie might be able to figure it out." She stood up from the computer, "Come on, let's go talk to him."

"Right behind you." Casey got off his bed and they left the room together, headed for the sewers.

+=0=+

 **A/N:Thanks all for reading! Remember to leave me your ideas and I'll try to fit them in. And sorry if there are any spelling or grammatical errors in the story. I don't have spellcheck on my new laptop. But I will reread the chapter just to make sure. Thank you and I'll see you all in the next chapter! MEOW!**

 **-Kittenclysm**


	9. Franz Hopper

**A/N: Hello, my kitties! I'm back with yet another chapter of Code: Mutation! I don't have to much to say, so let's go!**

 **Disclaimer: I do not own either show or their characters!**

+=0=+

Chapter 9)Franz Hopper

Donnie typed away on his computer, trying to find any information about the man that April discovered.

"Well, not much is coming up on him," Donnie said. "What if Jeremie is this Franz Hopper guy?" Casey suggested. "There's no way," April said, "Those journal entries were created 10 years ago, Jeremie would've been 5. There's no way he could've known how to figure out those computer codes and formulas."

"What can you find about him?" Leo asked. "The only thing that I did find is that he was actually a teacher at Kadic," Donnie said, looking at his computer. "Really?" April asked, "Can you hack the school system and find out more?"

"Already did," Donnie replied, "He lived in a house that's near here, but as for his teaching record, he hasn't been there for ten years. It's like he just disappeared off the face of the Earth without leaving a trace."

"What about his daughter?" Leo asked. "There's nothing listed in his records about him having a daughter, just a wife," Donnie answered. "Anthea?" Casey asked. "Yeah," Donnie answered, "How'd you know?"

"In his diary, he said something about going into the computer to rescue her. But he said that he was going to take his daughter with him and they would be the Guardians of something called Lyoko," April said, "And I think it has something to do with this factory."

"Here we go again," Casey sighed. April turned around and glared at him. "What?" Leo asked. "April keeps talking about some factory," the hockey player replied, "She keeps saying that we were all there, fighting Metalhead with some of our classmates."

"We were!"

"What if we check out Franz Hopper's house?" Leo asked. "What if there's someone there?" Mikey asked. "Well, if there's no record of him for the past ten years, I doubt he'll be there," Raph said.

"Okay, guys, let's go," the leader ordered. They left the lair, headed to the house.

+=0=+

The six teens stood outside of an old, rusted gated that had a plaque on it that read HERMITAGE. The house behind it looked just as decayed and abandoned.

"Uh...Donnie? Are you sure this is the r-right place?" Mikey stuttered slightly. "What's wrong, Mikey? Scared?" Raph teased. "N-no!" his brother replied.

"Come on, you two, knock it off," April said. She pushed the gate open with a loud squeak.

When they walked up the stairs of the front porch, they also let out terribly loud squeaks in each step. Suprisingly, the front door opened with no problem.

Inside the house, they saw a living room full of old, dusty boxes, which were full of worn out books and clothes, almost like someone was packing to move, but left everything behind. There was a fireplace on the far wall and a set of stairs that led to the second floor. "This place is creepy," Mikey said as they walked through the labyrinth of boxes.

Raph snuck up on him and tickled his neck, startling him and making him scream. He jumped in surprise and knocked over a stack of boxes, causing a few things to fall out of the top one.

"Raph!" Leo scolded. April looked down at one of the pictures that fell out of the box, "Wait a minute." She picked up a framed photo of a woman with long pink hair and a familiar looking man with gray hair and beard, wearing a pair of glasses. "What is it?" Leo asked. "I-I feel like I seen this guy before," April said, "And there's something about this woman, too."

"Huh, now that you mention, that woman does look familiar," Casey said, looking over April's shoulder and looking at the picture. "Donnie, do you think _this_ could be Franz Hopper?" April asked. "Well, the picture does look a little old, I suppose this could be him," the turtle answered, "And I'm guessing that must be his wife."

"Wait a minute," April said, "I know where I've seen him!"

+=0=+

Karai started to walk out of the bathroom, all ready for the day.

Just then, April sped past her at full speed. "Whoa, April! Where are you going?" she asked.

"Just running to get something from the room. Then, I'm going to go back to the lair," she replied, rushing into the room.

Karai ran into the room behind her. She saw her knelt down at the drawer under their closet, digging through the contents. "What are you looking for?"

"Got it!" April said. She slipped the picture into her pocket and sped by Karai again. "April! What's going on!" Karai shouted. "Just go have lunch and meet me in the lair after!" April said back, running to the door. Karai shrugged and went into the room to grab her phone and to let herself transform for a few minutes.

As soon as the door shut, she let her mutation take over and shapeshifted into her snake form. "Ah, that's better," she said. She slithered to the desk and took her phone off the charger.

She thought she heard someone coming down the hall, so she quickly shifted back. She opened the door and peered out, so she didn't notice the black form come out of the outlet next to the desk.

She shut the door and turned around, only to catch a glimpse of the form before it engulfed her body.

Her round pupils then turned into X.A.N.A.'s symbol. She stood up and headed to the lair.

+=0=+

April ran into the lair, where the boys were all waiting for her. "I got it!" she said.

"Alright!" Mikey said, "What'd you get?"

"This," she pulled out the picture that she found before the day started over and handed it to Donnie. Donnie stared at it increduously and then compared it to the one they got from the Hermitage.

"This is him!" he said, jumping from his seat. "But that doesn't make sense," April said. "What?" Casey said, looking at the picture, "Wait, is that...Aelita?"

"I thought it was, but she looks like ten or eleven in that picture. And if Franz Hopper hasn't been around for ten years, that would mean that Aelita would be in her twenties now," she said, "And how would she even be tied with him?"

"And Odd too," Casey added. "Odd?" Raph asked. "Another one of our classmates," Casey said, "He's Aelita's cousin."

Just then, Casey's cell phone started to go off, "Oh, great, it's Jeremie." He answered, "What's up, Jeremie?"

" _Casey, what did you do to our room?_ "

"What are you talking about?"

"All of my computer stuff and my laptop are smashed!"

April and Casey looked at each other. "W-well, I didn't do it!" he said.

" _Did you lock the door when you left?_ "

"Oops," Casey facepalmed, "Look, Jeremie. I can't talk right now." He hung up before the blond could say anything else.

"Who could've done that?" April said. "Probably Sissi or one of her proxies," Casey said.

April shook her head of the thought and turned back to Donnie, "Did you find anything out about a factory?"

"I think you should let this factory thing go," Leo said. "I can't," April said. She suddenly grabbed her head as a sharp pain came over her and the same eye symbol flashed in her mind. "Are you okay?" Donnie asked. "Yeah," she said as the pain began to subside, "Yeah, I'm fine," she took her hand off her head, "That was weird."

"Guys!" Karai called. They all looked over to see the snake girl, "April's right! I went and took a look in the city and there _is_ a factory down by the water, just like she said."

"Well, I guess we're going to go check it out," Leo sighed.

They started to leave the lair, with Karai being the last. X.A.N.A.'s symbol flashed in her eyes as they walked out.

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 **A/N:Again, thank you all for reading. And again, if there are any errors, it's because I don't have spellcheck, but I will go through and look for them. And I'll try to find a program with spellcheck and use that instead. Plus, I put that in about Karai tranforming because I feel like it would be a 'stress release' sort of thing. Let me know what you think of that. Remember to read, review and share. And leave me any ideas and I'll see what I can do. I'll see you in the next chapter! MEOW!**

 **-Kittenclysm**


	10. Supercomputer

**A/N: Hello, my kitties! I like to welcome my newest follower to this story, Indomiraptor. Hope you enjoy. And I'm also glad to say that I found a program with Spell/Grammar check, so that won't be a problem now. Anyway, let's get going!**

 **Disclaimer: I don't own anything in the story.**

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Chapter 10)Supercomputer

The three teens and four turtles stood at the entrance of the factory that they had once seen before, but only one remembers.

"See?" April said, "I TOLD you that there was a factory!"

"Sorry we didn't believe you, April," Donnie said. "I guess it's okay," April said. "Come on, let's get in there," Karai said. They saw her run into the factory, jump over the stairs and grab onto one of four ropes that hung from the ceiling that they hadn't noticed. "Uh, how did she know about those?" asked April. "Don't care, let's go!" Leo said. The turtles and Casey ran and jumped onto the ropes like Karai. April stood by herself, trying to think, she could feel there was something wrong with her friend.

They slid down the ropes and landed in front of a freight elevator. "Come on," Karai said, immediately walking into the elevator. "Whoa! Karai, where are you going?" Leo said, grabbing his sister's arm. "Leo, we don't have time for this," she said, "I have a feeling that there's something dangerous in there. Whatever it is, we have to take care of it before it destroys the world!"

They all looked at each other in contemplation. "I guess it couldn't hurt to just check," Donnie said. They piled into the elevator and Karai hit the button to go down.

The door opened and they all saw a large computer, sitting next to a three dimensional, holographic map, cut into four sections. "What is all this?" Raph asked, walking around and looking a the computer and map. "This must be the center of the anomalies that Donnie detected," Karai said. "Let me see," Donnie said. He walked over to the computer and got on it, "Incredible."

"What?" Mikey asked. "There's an entire digital world inside this computer. It's like an ecosystem made out of code!"

An alert with a red, tower-shaped object appeared on the screen. "What is that?" he asked. "It's probably some sort of alert that shows that this thing could case harm," said the snake-girl, slamming her hand on the keyboard, "We need to shut it down and destroy it immediately!"

"Okay, and how do you propose we do that?" Raph said, crossing his arms. "There's a mainframe a few floors below this room," she said, "We shut it down, then smash it. It's that easy."

"Okay, come on," Leo said. They got back in the elevator and, once again, Karai pressed the button to go down.

"Karai, how did you know all this?" April asked her.

"I did a little scoping out before I got you guys."

Once they got to the lower level of the factory, the door opened and they entered an empty, white room, but as soon as they entered a giant, cylindrical mainframe with two tiers, slowly emerged from the floor.

As they got closer, a panel with the same eye symbol, that only April recognized, opened and a handle popped out. "That must be the shut off switch," Donnie said. "Then what are we waiting for?" Karai said, "Let's just get this over with!"

Just as she said this, the symbol flashed in her eyes again, which April noticed. "X.A.N.A.," she whispered. She quickly scanned the room and spotted an old pipe off to the side. She quietly snuck over to it and picked it up without no one noticing. She came back over, hiding the pipe behind her back and stood behind Karai.

"April, what are you doing?" Mikey asked her. "Nothing," she said smoothly.

Karai walked toward the mainframe and reached for the handle. "NO!" April screamed as she ran to Karai and swung the pipe at her. The mutant easily dodge the attack. "April, what are you doing?!" Leo said. "Stopping her!" the kunoichi answered, trying another attack. "Why?" Casey asked, "Karai wasn't doing anything wrong!"

April continued to attack, until she finally got behind Karai and grabbed her, "Donnie! Tranq her!"

Donnie didn't understand, but pulled out a tranquilizer ball that he had been working on back in New York. He threw it at Karai, hitting her in the face.

The snake girl soon calmed down and went limp as she lost consciousness. April dropped her on the ground and breathed heavily. "What the heck was that?!" Raph asked. "Yeah, I've never seen Karai act like that, except when she was working for Shredder."

"That's because this _isn't_ Karai," April said, "Casey, call Jeremie and tell him to get the others and come to this factory."

"Uh...okay," Casey said, quickly pulling out his phone. "We gotta tie her up before she comes to," April said. "On it!" Mikey said. He pulled out a roll of duct tape and wrapped up the girl.

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"I just have no idea who would want to do this," Jeremie said. "What if it's X.A.N.A.?" Yumi said, "Like when he trapped me in a Guardian and sent a clone to Earth and she destroyed your stuff."

"Maybe," Jeremie said, thinking. "Hey, look at this," Ulrich said, moving one of the smashed devices. He picked up a white scale off the floor. "Is that a scale?" William asked.

Just then, Jeremie's phone rang.

"Hello?" he answered, "What? How did you find it? Karai? Okay, okay, we'll be there in a few minutes." He hung up the phone and put it in his pocket. "I think It was Karai," he told them. "Karai?" they said in unison. "Yeah," he said, "She's been possessed and led them to the factory."

They ran out the door and ran to the boiler room to take the passage to the sewers.

+=0=+

The Lyoko warriors came into the lab and saw April and Casey, standing alongside the four turtles, and Karai on the floor, unconscious and wrapped up with duct tape. "Whoa, cool!" Odd said, seeing the turtles. "What are you all doing here?" William asked. "Karai brought us here," said Donnie, who was still sitting at the computer, "What is this place?"

"Secret," Jeremie simply said, "Now get out of the chair before you ruin any of my work."

"Geez, I was only trying to help out," Donnie huffed. "Okay, get to the scanners and I'll send you to Lyoko," Jeremie said, "Let me just localize the tower." He pressed a few keys on the computer and it started a scan.

"Wait, you think it's a good idea to send us all to Lyoko?" Yumi said. "Yeah, I think someone should hang back, just in case Karai wakes up before Aelita can deactivate the tower," Ulrich agreed.

"It's okay," Raph said, "We're _professional_ ninjas, we can handle whatever she throws at us."

"Yeah, maybe if you were dealing with the real Karai," Odd said, "But she's being controlled by _X.A.N.A._ A dangerous entity," Odd said. "Okay, Aelita, Odd, Yumi, and William will go," Jeremie said, "Ulrich will stay behind."

"Got it, captain," Odd said, giving a mock salute. He, Aelita, William, and Odd got back in the elevator and it closed behind them.

"Where exactly are they going?" Casey asked. "To Lyoko," Jeremie said. "What's that?" Mikey asked. "A virtual world, cut up into different sectors." He continued to type and then spoke into his headset, "You guys ready?"

Yumi, Aelita, and Odd got into the scanners and the scanners all shut, " _Trans_ _f_ _er Yumi, transfer Odd, transfer Aelita. Scanner. Virtualization._ "

Once they were out of the scanners, William stepped in again and Jeremie repeated the process.

The four landed in the middle of the desert sector. " _Okay, the tower should be 18 degrees from your location_ "

"Got it," Aelita said. They took off toward the tower.

April looked over at Karai, still knocked out. Then she looked at over at Jeremie.

When he noticed her staring at him, he asked, "What?"

"You started the day over, didn't you?" she asked.

"H-how did you know about that?"

"Well, I wasn't sure what it was when it happened, but I remember being on the bridge outside and then I remember there being a bright light. Next thing I knew, I was back in our room," she explained, "So, spill it, what was that?"

Jeremie was about to start talking, but the computer started to beep. "Not now," he said, "Guys, there's some Bloks coming your way!"

April looked over at Karai again, "She was the one that destroyed you computer, wasn't she?"

"Karai? More than likely."

"Why'd she do something like that?" Raph asked. "Because, if I didn't have my equipment, we wouldn't have known that X.A.N.A., the one we're fighting, had launched an attack," he explained.

"Hey," Ulrich said, "Does this have anything to do with her?" He pulled out the scale that he had found in Jeremie's room. "Uh, yeah," Donnie said, "Karai is part snake."

"William, Look out!" Jeremie said into the headset.

"What's going on?" Casey asked. "William's just been attacked and devirtualized," the blond answered. "'Devirtualized?'" Mikey asked. "He just lost all of his life points and is being sent back here," Ulrich said.

After a few minutes, the elevator door opened and William stepped out. "Welcome back," Jeremie said. "I swear, I did not see that Blok coming up behind me," he said. "Blok?" Raph asked. "Don't worry about it," William said.

"Release me! Now!" Karai hissed in a distorted voice. They all looked down and saw that she was awake and struggling to get free. "Nice try, X.A.N.A., but we're not falling for that," Casey said. "Guys, look in my eyes," she said in her normal voice, looking up at them.

They looked at her and saw that her pupils were normal. "Will you please let me go?" she pleaded. "Okay," Mikey said. He took a step toward her, until Ulrich grabbed the top of his shell, "Mikey, no!"

He was pulled back just as Karai change into her snake form and tried to attack him. "Whoa!" Casey exclaimed. "What _is_ she?" William asked. "She's a mutant, like us," Leo said, struggling with her, "Donnie!" Donnie reacted by hitting her with another tranquilizer ball, knocking her out again.

"Well, that's makes a lot more sense," Ulrich said as Leo laid Karai on the ground. Something suddenly hit Mikey, "Hey, how did you know my name?"

"Huh?" Ulrich said. "Just now, when you pulled me away from Karai, you said my name," Mike replied. "Well, I don't think you'd understand if we explain it to you," Jeremie said.

" _Uh, hey, Einstein?_ " Odd said on the computer.

"What's wrong, Odd?"

" _Well, our old friend has a line of Tarantulas and Krabs set up in front of the tower and we can't get past them!_ " Yumi said, " _We could use a little leverage._ "

"Got it, vehicles coming right up." He entered a few codes and they showed up in front of them, which they jumped onto without a second thought and flew over the monster, taking out a few in the process.

"Okay, this should all be over in a minute or two," Jeremie told the others in the room. "That's good," Donnie said, "Because I'm not sure how effective the tranquilizer will be this time."

A tarantula fired a laser and hit Yumi in the chest, devirtualizing her.

"Okay, Odd, it's up to you," Jeremie said. " _Too easy_ ," Odd said, flying over the others and dropping Aelita off at the foot of the tower. She ran in and began the process.

"Okay, she's in," Jeremie said, "Won't be long now."

Karai suddenly jumped awake, mutated herself again and ripped the tape that restrained her. She ran to William first and tightly grabbed his arms so he couldn't get away. She bared her fangs and him and leaned forward, prepared to bite.

The dark aura suddenly left her body and she shifted back to her human form. William put out his arms and caught her as she went limp.

"Is she okay?" Raph asked, the six New Yorkers gathering around her. "She'll be fine," Jeremie said, turning back to the computer.

A few seconds later, Karai opened her eyes and looked up at William. She blushed as he let her go. "W-what happened?" she asked. "Apparently, something attacked April earlier and I think it took control of you when it couldn't do it to her," Donnie said, "Did I get that right, uh..."

"Jeremie," he said, typing on his computer, "And yes, that's right."

"Jeremie, what are you doing?" April said. "I'm setting up to go back in time," he replied, "That way, no of you will remember any of this," he kept typing and went to press the final key, "Return to the past, n-"

"Wait!" April said, grabbing his arm. "What?" he said.

"We want to help."

"Are you sure? It's pretty dangerous," Ulrich said. "Hey, we went up against alien robots, homicidal mutants, and the man that killed our father!" Leo said. "Whoa! What?" Odd said, "It's hard to explain," Karai said, casting her gaze to the side. "Well, how about we make a promise," Jeremie said, "We _have_ to do a jump back in time, but if you by chance remember this, we'll explain everything and you can join our team?"

"Deal," April said. "Okay, in that case, return to the past now," Jeremie said. He hit a few more keys on the keyboard and the same white orb that April remembered appeared in the middle of the room, expanding and engulfing them all once more.

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 **A/N: Thanks for reading and I want to let you all to know that I'm going to start a sequel to my other fanfictions, Of Gems and Mutants, which shouldn't be a too long story, but will be at least a few chapters long, but I will still be working on this one. So just remember to read, review, and share, and I'll see you in the next chapter! MEOW!**

 **-Kittenclysm**


	11. Joining Lyoko

**A/N: Hello again, my kitties! I'm back with a new chapter again. I'd like to welcome my newest followers, Caliban Super Saiyan 0 and Xinext. Thanks for following and I hope you enjoy. I really get excited when I get new followers. Let's go!**

 **Disclaimer: I don't own either show or characters**

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Chapter 11)Joining Lyoko

This time, when April opened her eyes she was standing inside the bathroom, with Aelita just a few feet away from her, brushing her hair. "Okay, are you going to explain everything now?" she asked her. "What are you talking about?" Aelita answered; April looked through the showers, making sure they were completely alone. "About the factory," she answered after she saw there was no one there.

"I'll, uh, I'll have to talk to Jeremie first."

"Good, because we really want to help out as much as we can."

Aelita thought for a minute, "I think I can talk them into it."

"Cool," April said as they left the bathroom, "Let me see if I can get Karai up this time." April went back to their room to wake up her friend and grab something.

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"Why did you have to make this deal with them?" William asked. "To be honest, I was hoping that April would forget this time," the young genius replied, "It just doesn't make sense how she _does_ remember everything. Only people scanned into the computer remember. But I guess it won't hurt to have more people on our team."

"Especially people who know how to fight like them," Ulrich said.

"Hey, guys," April said, coming up to them with Casey and Karai behind her, "You ready to explain everything?"

"April, I still don't understand, what do they have to explain to us?" Casey asked. "The factory, the supercomputer, Lyoko and why we've repeated this morning three times," she answered. "'Repeated this morning?'" Karai said, "I swear, you've lost your mind."

"No, she hasn't," Jeremie said, "All the things she said are real and really happened."

"Yeah, right, then tell us something that's gonna happen," Casey challenged. "Well, we can't tell _exactly_ what's going to happen, because this is a different timeline than the other two, but we can tell you something that only you would know," Aelita said. "Okay, tell us," Karai said. "Well, we know that your four younger brothers are turtles," Yumi whispered so that no other students could hear her. Karai gasped and leaned toward her, "How did you know that?"

"Because, like April said, we've done this three times," William admitted. "We can show you when we get there," Odd said, with a mouthful of food, "And you can bring your brothers and I can finally officially meet them."

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After they finished breakfast, Jeremie and the others led Karai and Casey to the factory, with April going to the sewers to get the turtles.

Once they were all gathered in front of the factory, Aelita noticed that the turtles looked a little uncomfortable near them. "Oh, come on you guys, you don't have to be like that," she said, "We already knew about you."

"You did?" Mikey asked. "Come on," Jeremie said, walking toward the factory, "Let's go."

They watched as Jeremie, Ulrich, Odd, and Yumi run in and grab onto the four ropes, quickly sliding down them. Aelita and William soon followed.

The turtles, Karai, and April shrugged and followed, but ignored the ropes and landed. Casey, on the other hand, had to use the rope, since he was still training.

They landed in front of the freight elevator and all got in.

When they got down to the supercomputer, the turtles, Casey, and Karai looked at everything in astonishment.

"Okay, Belpois, explain," April said.

"Well, I guess just telling you from this point would be slightly confusing, so I'll start from before we all became friends," Jeremie said. "Wait, you weren't all friends when this started?" Casey asked. "No, actually, it was the computer that brought us together," Odd said.

"A few years ago, I was working on a robotics project, so I came to this factory to look for any extra parts that could be useful," Jeremie started, "When I got here, I discovered the supercomputer. "I was curious, so I switched it on. That's when I discovered Lyoko and what I thought was an artificial intelligence that lived inside."

"X.A.N.A.?" April asked. "No, he didn't rear his ugly head until later," Jeremie said, "This was a girl, who had no idea who she was or why she and Lyoko was created."

"She didn't know anything?" Leo asked. "No, not even her name, so we decided to call her Maya until we figured out more," Jeremie continued. "At the same time, me and Odd had just met and we didn't really get along too well," Ulrich said. "Why's that?" Raph asked. "Well, it mostly had to do with Kiwi at first," the brunette replied.

"Kiwi?" Karai asked. "My dog," Odd answered. "I thought pets weren't allowed at Kadic," Casey said. "Oh, they're not," Yumi said, "That's why they hide him in their room."

"We don't have to worry about you telling anybody about him, right?" Ulrich said. "No, of course not," Casey said, "I mean, it's obvious that we can keep a secret."

"Anyway, I wanted to learn more about Maya and Lyoko, that's when I discovered that there were scanners in the lower level. I needed a little help, so I went to Ulrich," Jeremie continued. "Since I wasn't exactly getting along with Odd and Jeremie wanted a test subject for the computer, I took Kiwi and tried to put him in one of the scanners," Ulrich said. "I saw Ulrich take my dog, so I followed him here," Odd continued, "I tried to take Kiwi out of the scanner, but then I got in it. I was scanned, then sent to Lyoko."

"When X.A.N.A. attacked, we figured that we had to go into the computer to solve it and we thought that we needed more help, so I went to Yumi, who I had just met through our karate lessons," Ulrich explained. "Well, if X.A.N.A.'s as dangerous as you say he is, why didn't you just pull the plug as soon as he attacked?" Donnie asked.

"Because I wanted to figure out how to materialize 'Maya' and get her out of the computer before we did," Jeremie said, "I would've felt bad if I just shut the computer off and left her trapped in there."

"So, we went into Lyoko to help her try to find out how to do it," Yumi said. "Did you?" Mikey asked. "Not at that time," Ulrich said, "But we did figure out how to stop X.A.N.A.'s attack and discovered Maya's real name."

"What was it?" Casey asked. "Aelita," Jeremie answered, looking over at the girl. "Wait, I thought Aelita was Odd's cousin," April said. "No, that's just what we told everyone when we enrolled her into Kadic," Odd said. "It took us a long to time to figure out the materialization code, but when we got her out, we needed to make a false identity for her," Ulrich said.

"So, why didn't you shut it off when you got her out?" Raph asked. "We did," Jeremie said, "But Aelita was missing something that was keeping her linked to Lyoko," Jeremie said, "If we shut off the computer, not only would X.A.N.A. die, Aelita would have too."

"And now?" Leo asked. "Well, X.A.N.A. freed himself by stealing fragments of Aelita's memory," Jeremie explained, "Fortunately, she got them back and she's free now, but so is X.A.N.A."

"Wait a minute," April said, "So you're saying that Aelita was like a guardian of Lyoko?"

"Yeah," Ulrich said, "Basically."

April thought back to the journal that she read on Jeremie's computer, "Do you know anything about someone named Franz Hopper?"

Everyone seemed to freeze at the mention of his name. "How do you know about him?" Jeremie said. "I read his journal on your computer," she replied, "And Donnie searched for any information about him. Plus," she pulled out the picture she found in their room, "I found this."

They all looked at the picture of Franz and Aelita, "That _is_ him, right?"

"Where did you find this?" Aelita asked. "In our room," the red head answered. "I have to say, this girl does look a lot like you, Aelita," Casey said, taking the picture. "That's because it is me," she said, "That was me before we went into the computer."

"So you _are_ linked to Franz Hopper?" April said. "Yes," Aelita said, looking down, "He was my father. I wasn't a computer program. When we thought I was a computer program, we thought that X.A.N.A. just infected me with a virus before I left Lyoko, but the real reason I was linked to Lyoko was because one of my memory fragments was missing. That's why I couldn't remember my life on Earth."

"What happened to him?" Karai asked. "He was in the computer too, but he sacrificed himself so we could beat X.A.N.A. the first time," Odd said. "But Aelita thinks that he might still be in the internet somewhere," William said. "We figured, as long as we have to keep the supercomputer on to fight X.A.N.A., we can try to look for him," Yumi said.

"You know, you might be the people that this guy told us about," Donnie said. "What guy?" Aelita asked. "We don't know who he is," Leo explained, "He sent us a message saying that he wanted our help."

"He enrolled us in school here and told us that there were six people that could help us. I think he was talking about you," April said. "And you don't know who he is?" Jeremie asked, "Did you try tracking him?"

"Can't," Donnie replied, "He scrambled his IP address."

"Lemme see."

Donnie opened the email on his T-phone and handed it to the genius. Jeremie looked at it for a second.

"Hold on," he said, "That's not an IP address."

"What is it then?" William asked. "It's a genetic code sequence. And I think it looks kind of familiar, don't you, Aelita?" Said girl looked at the phone with him.

"I don't believe it!" she exclaimed. "What?" Ulrich asked. "This is Franz Hopper's genetic code sequence," she said softly, "My father's alive. I knew it!"

"Then we really _can_ search for him," Odd said. "How can you do that just in this virtual world?" Leo said, "What's it called again?"

"Lyoko," Jeremie answered, "And there's a way to get into the internet through it."

"After X.A.N.A. got out of the supercomputer, when we went into Lyoko, he took control of Aelita and used her to delete the four sectors of Lyoko. He was still able to attack by making replicas of the sectors in the internet," Jeremie explained, "Luckily, we found a way, so we could stop him. Plus, I recreated all the sectors."

"Now we just have to beat X.A.N.A. again," William said, "And I get to help this time."

"You didn't last time?" Mikey asked. "Well, he was recruited when X.A.N.A. started to get too tough for just the five of us," Odd said. "And on his first trip, he got cocky and got possessed," Ullrich added. "I spent months in the computer after that," William said.

"How'd you keep Delmas from finding out?" Karai asked. "Jeremie used the same method that X.A.N.A. uses to attack to make a clone of William. "And what if William's parents called the principal or he called them?" April asked. "Had that covered," Jeremie said. He started typing on his computer, and suddenly, April phone rang. She looked at it and saw it was an unfamiliar number. "Hello?" she answered.

" _Hello, this is Headmaster Delmas at Kadic Junior High School,_ " she heard Jeremie and the voice over the phone, which sounded like the principal, say. "How did you do that?" she asked him, hanging up. "I created a voice modulator shortly after William got stuck in the computer," he said, "Just for that."

"But enough about us, what about you?" Ulrich asked, "Why are you like... _this_?"

"Well, I guess the story starts with our father," Leo began. "Well, biologically, he's Karai's father, he adopted us," Donnie said. They all looked to Karai for the story then and she began,

"My father's name was Hamato Yoshi. He lived in Japan and was a part of the Hamato clan, anyone born into that family full was trained to be a ninja. The Hamato clan had taken down another one, the Oroku clan. That's when they adopted the remaining child, Oroku Saki. Yoshi and Saki were raised learning the same techniques and secrets. They were great friends, brothers even, until they both fell in love with the same woman," she pulled out the picture of her parents standing next to each other, "Tang Shen."

"Your mother?" Aelita asked. Karai stayed silent. "What happened?" Ulirch asked, turning to the others. "Saki's anger consumed him," Leo continued, "Eventually, the only thing he could think about was getting revenge on Yoshi. He took everything from him. His wife, his home," he pulled out the picture of Splinter's family, "And his baby daughter, Miwa."

"Miwa?" Odd asked. "Wait, is that..." Yumi began, then turned to Karai. "Saki took Miwa away and raised her to believe that Yoshi was the one that killed her mother," Donnie said.

"Without a home or family, Yoshi fled Japan and moved to New York City, which is where Tang Shen wanted them to move," Leo said, "When he got there, he adopted four baby turtles from a pet shop."

"On the way home, he was passed by a man in a suit that seemed strange to him, so he followed," Raph said. "He followed him into an alleyway, where he met another man in a suit. They were exchanging a canister filled with a strange glowing ooze. Yoshi knew he had to do something, so he attacked."

"During the fight, the canister broke and the ooze spilled onto Yoshi and the four turtles," Leo explained, "The mutation turned the turtles into, well, us and it mutated Yoshi into a man-sized rat." Leo pulled out the picture of Master Splinter and the four of them as kids. "But, how?" William asked. "Well, the contents of the canister was mutagen. It was created by a race of aliens from a different dimension called the Kraang," Donnie explained, "They were planning on terra-forming the Earth with it, but the mutagen had different affects in our dimension than it did theirs."

"What about you guys?" Aelita asked. "Well, the Kraang were looking for the five of us, but when he hid in the sewers, he found that the Kraang's tracker didn't work down there, so he created a small home in the sewers," Leo answered, "Then, he discovered that we were copying him as he did his ninjutsu training, so he decided to train us as Master Splinter."

"On our fifteenth Mutation Day, that's what we called our birthday, we asked him if we could go up to the surface," said Leo, "He agreed, but told us to stay hidden."

"That's when I met them," April said. "We spotted her and her father on the street just as a couple of men in suits drove up to them and kidnapped them," Mikey said. "What we didn't know was that those men were a couple of Kraang droids," Raph said. "So, what happened to your father and Saki?" William asked.

When no one said anything, April cut in, "Uh, how about we get this done? We want to join already!"

"All right," Jeremie said, getting out of the computer chair, walking to the elevator, "Follow us."

Everyone got back in and Jeremie pressed the button.

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The turtles and their friends looked at the bright tubes in amazement and confusion. "What are these things?" Raph asked. "This is how we get to Lyoko," Yumi said. "Here's how we're going to do it," Jeremie said, "I'm going to send Yumi, Ulrich, Odd, Aelita, and William before you, then I'll scan you guys into the computer then send you."

"Got it, chief," Raph said. "Just listen for my instructions," Jeremie said as he entered the elevator again.

A minute passed before they heard his voice through the speaker,

" _Okay, first, let William, Odd and Ulrich get in._ "

The three boys stepped into the scanners and the doors shut behind them.

" _Transfer William, transfer Odd,_ _t_ _ransfer Ulrich._ _Scanner. Virtualization._ "

When the doors opened, the seven gasped as they saw the boys were gone.

"Okay, our turn!" Aelita said. She and Yumi got into the scanners and the doors closed again, Jeremie starting up the process once more, " _Transfer Yumi, transfer Aelita. Scanner. Virtualization._ "

The doors opened again, seemingly calling to them. "I-I don't know about this, dude," Mikey said nervously. "We'll do it first if you're too chicken," Casey teased. "Okay, Jeremie, it's me, Casey and Karai," April called.

" _Got it._ "

The three stepped into the scanners and the doors closed. " _Okay, this is going to_ _be a little different,_ " Jeremie said. The turtles waited while he did it,

" _Scanner April, scanner Karai, scanner Casey._ " They heard the scanners cool off before they turned on again, " _Okay, now I'm doing the transfer. Transfer April, transfer Karai, transfer, Casey. Scanner. Virtualization._ "

The three landed in what looked like a forest, but instead of normal ground, they were on a floating platform that looked like actual earth. They realized that everyone was there and they all looked different. "Welcome to Lyoko," Odd greeted.

They looked at each other and noticed they all looked different, too. Karai was back in her clothes that she normally wore in New York, with a laser gun strapped to her hip. "Ah, that's much better," she said. Casey was wearing what looked like a silver version of his hockey uniform, with two hockey sticks symbols crossed on his chest and a titanium hockey stick on his back. "Awesome!" he said, taking the hockey stick.

April was wearing a yellow, knee-length dress, with a red sash wrapped around her stomach, a dark blue, long-sleeved robe and a pair of zori that matched her dress. Her hair was now pulled up into a bun, but most of it still hung down to her shoulders and in front of her ears with bangs barely reaching the top her eyes. The most noticeable was the necklace around her neck. It was mostly made up of large, light-blue beads, but in the middle was a golden swirl with an opening in the center. "Huh, simple," she said, "But I like it."

" _Alright, I'm going to do the turtles now,_ " Jeremie said.

Leo stood in front of the scanner, hesitant to the action. "Come on, Leo! Let's go!" Raph said. "Uh, how about you guys go first?" Leo said, moving out of the way. Raph went into the scanner, with Donnie and Mikey taking the other two.

The doors closed, leaving Leo alone.

Once their Lyoko avatars were created, Jeremie started the transfer again, " _Transfer Raph, transfer Donnie, transfer Mikey. Scanner. Virtualization._ "

As Jeremie finished, the red exclamation point appeared on the screen. "Oh, no," he said. He quickly typed on the computer, then got on his headset, "Guys, are Mikey, Raph, and Donnie on Lyoko with you?"

"No, they're not here. What's going on?" April asked. "I'm not sure," he replied, typing again, "Leo, are they in the scanner room with you?"

"No."

"Hurry, get up here," the boy ordered. Leo ran back to the elevator and went to the lab.

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 **A/N: Sorry I always leave cliffhangers, I know it's cliché. But I hope you enjoyed the chapter either way. Plus, I hope you like their Lyoko avatars. I actually got the idea for April's avatar from a girl in an anime that I got hooked on when I watched the YouTuber, Kubz Scouts, play its game. I want to see who can guess the character first. I haven idea what I want the turtles' avatars to look like. Sorry to gwencarson126, but I don't really see their spirit quest outfits really fitting into Lyoko's atmosphere. Sorry. But I do appreciate the ideas. Thank you so much! Also, check out my other new stories! I guess I'll see you in the next chapter! MEOW!**

 **-Kittenclysm**


	12. Coding Problem

**A/N: Hello, my kitties! Welcome back to Code: Mutation! I'd like to greet my newest follower, 1manApocalypse. Welcome and I hope you enjoy the story. Anyway, let's go!**

 **Disclaimer: I do not own either show!**

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Chapter 12)Coding Problem

"Jeremie, what's going on?" Leo asked, running into the lab. "I don't know," Jeremie replied, "Something went wrong during the transfer. I can't find them. At least, not on the outer layer."

"Outer layer?" the blue-masked turtle asked. "Yes, that just means I can't find them between here and Lyoko," Jeremie said, "Hopefully, there's not too much to worry about, these kinds of accidents happen all the time."

"Well, if they're not on the 'outer layer,' like you said, could they still be in the supercomputer?"

"Let me see, I'll run a scan. If they're anywhere in there, they'll get picked up."

After a few seconds, the computer started to beep. "Found them," he said. "Are they okay?" Leo asked. "They're fine, but their particles are divided and scattered throughout Lyoko," he replied.

"So what do we do?" Yumi asked. "You guys are gonna have to go to Sector 5 so that Aelita can gather the particles there and she can reassemble them," Jeremie explained, "Sounds simple enough," Ulrich said.

After he said this, another alert came on the computer screen. "What's that?" Leo asked. Jeremie hit a few keys, "Uh-oh."

"Now what?" Karai asked. "Well, it seems that the scanners have been infected by some sort of virus," Jeremie said, "I'll have to fix that before you go."

"Why's that?" April asked. "Because if something happens to us, something might go wrong and we can't get back to Earth," Aelita said. "I'll have to fix the virus before anything else," Jeremie said, "I have a program for that on a CD in my room. But I can't leave you guys alone."

"I can take your place until you get back," Leo offered. Jeremie looked between the computer and turtle a couple times before saying, "Alright, keep an eye on things and I'll be back in a few minutes. He took off his headset and gave it to Leo, "Let me know if anything happens."

"Got it," the leader turtle said, putting on the headset and took the chair in front of the computer. Jeremie then left the lab.

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The teens stood in the middle of the virtual forest in complete silence.

William glanced at Karai, April, and Casey. April was sitting on top of a nearby rock with her eyes closed, Karai was sitting on the ground, running her fingers in the digital earth, apparently lost in thought, and Casey was swinging his platinum hockey stick around. He attempted to spin it, until he hit himself in the head, then dropped on the ground, pretending to be knocked out. His gaze then went back to Karai, "Um, hey, Karai?"

She moved her eyes to look at him, but kept facing the ground, "What?"

"I was just wondering, how did you get your snake powers?"

She looked away from him, once again, staying silent. William stood back and slightly bowed his head, "Sorry, I didn't know that was a touchy subject."

"When I found out that Splinter was my father, Shredder trapped me," Karai said, "He thought that if I were a mutant, like most of them, I would go berserk and attack Splinter. When that didn't work, he had his scientist, Baxter Stockman, create a bug that took control of me and made me attack my own family." She lowered her head and closed her eyes, becoming silent.

"I'm so sorry," Aelita said.

"I hope the guys are okay," Casey said, sitting up.

"Why doesn't Jeremie just do that time travel thing that April was talking about?" Leo asked. "That's actually a really bad idea," Yumi said, "When an accident like this happens, using the Return to the Past can have unpredictable effects. If we do that, they might get lost in the computer forever."

"Hey, is April okay? She's been sitting there for a while," Odd asked, noticing her stillness. "She's more than likely in a deep meditation," Karai said, "When a person is in deep meditation, they can actually detach themselves from others."

"Especially April, since she has psychic abilities," Casey said, standing up. "Psychic abilities?" Aelita said. "Like this?" Yumi said. She moved her hand toward a small rock and it started to levitate as they noticed she was glowing. "One of them, yeah," Casey said. Yumi moved the rock and threw it over the edge of the plateau. After it fell, a beam of light shot into the sky. "What was that?" Karai asked. She and Casey ran to the edge and looked over, seeing a seemingly endless sea of white water.

"Water?" Karai asked. "That's not water," Ulrich said, "That's the digital sea."

"Be careful," Odd said, "You fall in there, you never come back."

"Has that actually happened?" Casey asked. "Once," Ulrich said, "Yumi fell in."

"But...she's right there," Casey pointed out. "Well, Jeremie was working on Aelita's materialization program and while he was out of the room, Odd accidentally dropped some candy on his keyboard. Somehow, the candies actually hit the right keys to complete the program," Yumi explained. "The problem was, since Jeremie didn't see the keys they hit, we only had one shot to materialize Aelita," Ulrich continued. "But then Yumi fell into the digital sea. We went back in time, but she didn't come back. So there was only one option. I had to give up my place so they could bring her back."

"That was a good thing to do, Aelita," Leo said.

The swirl on April's necklace started to glow and she snapped out of her meditation. "What's that?" she said, looking in the path on their left. They all looked that way, but saw nothing. "April, what are you talking about?" Karai asked. "I saw something," the psychic said, keeping her eyes locked in the one direction.

The computer started beeping and Leo saw five red symbols heading toward his friends.

"Uh, guys, there's something coming at you, and I highly doubt they're friendly," he said.

They all looked back and saw five, giant, bug-like creatures, except they were walking on four legs. "What the heck are those?!" Casey exclaimed. "Tarantulas!" Yumi said. The monsters ran until they came in front of them. They seemed to move their back legs so that they were in a sort of crouch-like stance and aimed their front legs in front of themselves. "What are they doing?" Karai asked. She looked at the Lyoko warriors and saw they all had weapons drawn. Except for Odd, who had his hand in a fist, pointed toward the monsters. "You have weapons?" she asked. "Yeah, you should too," Aelita said as she created a pink ball in her hands.

Karai then noticed the laser gun strapped to her hip and pulled it out, "Cool." She aimed it at one of the tarantulas and fired. She hit it and it screeched, but only seemed slightly fazed. "Yeah, these are some of X.A.N.A.'s tougher monsters," Ulrich said, using his katana to block a laser. April felt around herself and found a metal tessen tucked in her sash around her waist. It looked like the one she got from Splinter, minus the Hamato seal on it. She ran and threw it at a different tarantula. Like the one that Karai hit, it just screeched and went back to fighting.

A tarantula fired a laser and hit Karai, knocking her to the ground. She touched the spot where she was hit, expecting some kind of pain but didn't feel anything. William ran straight for the monster and plunged his Zweihänder into the symbol on its face. It let out a louder screech then exploded into pixels. "And that's how you do it," he said. He held out his hand and helped her up.

She looked down at the spot where she was hit and didn't even see a burn mark. "What the heck?" she said. "Yeah, when you get hit here, you don't feel pain," William said, "But try not to get hit anyway."

The phone on the computer started to ring. Leo hit a few keys and was able to answer it, "Hello?"

" _Leo, do you need help?_ "

"Yeah, how did you know?"

" _My computer at school is linked to the supercomputer. I can see everything you can._ "

"You can?"

" _Yeah, now listen, you can't let anyone run out of lifepoints,_ " Jeremie said, " _At least not until I can get the scanners fixed._ _I just found the disc to fix the virus. I'm on my way._ "

"Okay, hurry," Leo said. The phone window closed as Jeremie hung up.

April held up her tessen as one of the tarantulas fired at her. Yumi told them that some of their weapons could be used as protection. Her tessen glowed blue for a second, but then changed back to the same silver it was. She looked at it, confused for a minute, but then tossed it again. The tarantula she hit screeched and exploded.

"This stinks," Casey said, "Everyone gets cool weapons and I just have a hockey stick! Now I know how Donnie feels!" He stomped his foot and saw a light-blue hockey puck fall out of a slot on his skate. "What the heck?" he said. He used his stick to hit the puck at a tarantula and it froze in place as soon as the puck made contact with it. "Oh, cool!" he said, "No pun intended." He laughed at his joke, to which Karai and April rolled their eyes at the boy. "Odd, get it before it thaws!" Ulrich ordered. "On it!" the blond said, "Laser arrow!" An arrow shot out of his wrist, striking the frozen creature.

"Wait, so my weapon just freezes things?" he said. He then noticed a dial on the hockey stick in his hands. There were several colored dots around the dial and it was currently pointed at the light-blue one. He switched the dial to a red dot. He stomped his foot again and a red puck fell out this time. He shot it and it hit another tarantula, which then screeched as it apparently burst into flames. "Awesome!" he said. "Yeah, but be careful," Odd said, "You might have a limited amount of pucks, like my laser arrows."

Leo looked at Casey's avatar card on the screen and spotted a number next to what Leo assumed to be his attack status, "Odd's right, Casey. You only have 23 pucks left."

"Okay," Casey said.

April's necklace glowed again and she ran, pushing Aelita to the side just as a laser wall split between the group. "What was that?" Karai said. "Mega-tank," Yumi said as a giant black ball rolled up. "This one's pretty tough, too," Ulrich said. "Why's that?" Casey asked. "Because you can only hit it when it's about to attack.

The Mega-tank split open, revealing the symbol that they had to hit. It charged up before firing again. It's giant laser hit Karai, throwing her a few yards from the others. It shut as soon as the laser was fired. "Now I see the challenge with this one," April said. "I'm on it," Ulrich said. He ran over to the ball, yelling, "Over here you over-sized bowling ball!"

"Ulrich, are you nuts?" April asked. It turned toward him as he withdrew his katana again. It opened again, ready to charge. "Triangulate!" he said, starting to run around the Mega-tank in a three-sided formation. He ran so fast, that it looked like there were three of him.

The Mega-tank seemed confused, looking between the three Ulrichs. He leaped from one of them, his weapon meeting the center of the symbol. He pulled it out and jumped off just as it exploded like the others.

"That was awesome!" Casey said. "Well, X.A.N.A. is powerful, but he's still a computer program, which means he gets confused easily," Yumi said. "Kinda like Odd on his science tests," Ulrich said. Everyone laughed at his joke. "Ha ha, very funny," Odd said sarcastically.

The elevator door opened and Jeremie stepped out. "Okay, Leo, I'll take it from here," he said. Leo moved out of the way, letting the boy take control again. "Okay, guys, I'm back," he said, "Now, head to the edge of the sector and I'll call the transporter."

"Man, I wish we didn't have to take the transporter. It always gives me motion sickness," Odd whined. "Stop complaining, we have to save my brothers," Karai said. "Okay, follow us," Aelita said, running away, everyone running after her.

After a few minutes of running, they made it to the edge of the plateau. "Great, now where do we go?" Karai asked.

"I'm on it," Jeremie said as the Carthage window popped up, "Haven't done this in a while." He typed in SCIPIO and pressed the ENTER key.

Casey, April, and Karai slightly stepped back when they saw a giant eyeball come out of the digital sea and float toward them. It opened up and grabbed all eight of them, Then, took off.

"Holo-sphere, online," Jeremie said, as the holo-map in the lab changed from the four sections into a large sphere with several tunnels spouting from it. "Whoa," Leo said when he saw it switch.

After a minute or two, the transporter gently landed in the center of the drop off. Odd let out a nauseous moan as he tried to settle himself. "Whoa, where are we?" Karai asked, looking at the spinning wall around them. "Sector 5," Yumi said, "It's like the inside of X.A.N.A. and the center of Lyoko."

"It holds all the information that makes up Lyoko," Aelita said, "We just have to get through the corridor and to the terminal on the edge of the sector."

"Okay, you work your way to the terminal and I'll disinfect the scanners," Jeremie said, inserting the disc, "The wall's opening up." As soon as the wall stopped, the passage opened and they ran through.

They entered a large room with dozens of floating panels replacing the floor. "Okay, be careful. X.A.N.A. might've booby trapped the room," Ulrich said. "Yeah, and beware of Creepers," Odd added. "Got it," Casey said.

They hopped from one panel to another, until Casey hit one that turned red and disappeared from under his feet. He was able to grab onto the ledge before he fell. Yumi pulled him out of the hole. "Told you," she said. "Thanks," Casey said, brushing himself off. As they were walking away, Casey heard a gurgling sound come from the hole he was pulled out of. He turned around and watched as two brown limbs emerged from the hole, pulling out a creature with two front limbs and a dark silver tail. It growled and opened its mouth, revealing its laser.

As soon as it fired, Casey put his arms together, trying to block the attack, and was surprised when a glowing dark-blue shield appeared in front of him. When he lowered his arms, it disappeared. "Awesome!" he said. Two more Creepers crawled out of the hole and came at them. The three surrounded the New York teens.

One of them fired at April, who blocked it with her tessen. Once again, her weapon glowed blue. It was then that she noticed a gauge on the bottom that was one third full. "What the..?" she said, but had to block another laser. It glowed again. She looked at the gauge and it was now halfway full. She thought for a minute then came up with an idea.

One of the Creepers swept its tail at Karai, knocking her off her feet and hit her with another laser. " _Karai, be careful! You only have 15 lifepoints left!_ " Jeremie warned her. It fired again, but April's tessen got between it and Karai, protecting her from the attack.

When the fan returned to the user, she looked at the gauge again and this time, it was three quarters full. "That's what I thought," she said. She waited until another Creeper fired at her and she blocked it again. This time, the gauge filled up entirely and the tessen started to glow blue. "Whoa! What happened to your weapon?" Odd asked. "I think it just got supercharged," she replied. She let the three Creepers surround her and she threw it.

In one attack, it took out all the monsters. "Good job, April," Casey said as she caught it. When it made contact with her hand, it changed back to its normal, metal appearance.

They kept running until they made it to the outside of the dome and there was just a screen in front of them. "This is it," Aelita said, "Protect me."

"Got it, princess," Odd said. He and the other Lyoko warriors stood on either side of her, getting into fighting positions as the pink-haired girl accessed the screen.

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 **A/N: I know this chapter was a little long, but I just couldn't stop typing! I hope you like their weapons. The ideas for Casey and April's weapons just kind of came to me while I was writing. Anyway, like I said in the last chapter, I want to see if anyone can guess where I got the idea for April's Lyoko avatar from. It's from an anime that premiered back in 2016. Anyway, remember to read, review and share and I'll see you in the next chapter! MEOW!**

 **-Kittenclysm**


	13. Lyoko Turtles

**A/N: Hello, my kitties! Sorry this chapter took so long, but I was working on my other fanfiction and had a little trouble writing that one and this one was a little difficult to write too. I'm not sure if Kaijutamer25 started following before or after the last chapter, so I'd like to welcome you, too! Anyway, let's go!**

 **Disclaimer: I only write this for fun! No monetary gain!**

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Chapter 13)Lyoko Turtles

The three teens looked at the others as they stood on the small platform while the pink-haired girl worked on the screen. "How's it going Aelita?" April asked worriedly. "It's going to be at least another few minutes," she replied, "I have to gather all their particles and then transfer the information to Jeremie so he can sort, debug and reassemble them, then he can send them back here and, hopefully, if everything goes right, they'll get virtualized here."

"And if things don't go right?" Karai asked. "They may not come back," Yumi said.

"Hey, why are you standing guard like that?" Casey asked, noticing them standing on the sides of the platform. "Creepers aren't the only monsters in this sector," Odd said. "Okay, what other monsters are there?" Karai asked.

Once again, the golden spiral on April's necklace glowed before Ulrich stated, "They're hatching!"

They looked at the blue wall of the sector, just as five stingray looking creatures emerged from it. "What are those?" Casey asked. "Manta Rays," Odd replied, "Hey, Einstein, we could use some leverage here."

"I'm trying!" Jeremie said to him. He opened the vehicle virtualization program and entered the code to call them in.

"Whoa! What are these?" Casey asked when he saw the three vehicles. "Just a little thing that Jeremie created to make it easier on us," Odd said, jumping on his Overboard and Ulrich and Yumi got on theirs. "You wanna hop on?" Yumi asked. "I call Odd!" April exclaimed, jumping behind the blond. "Alright!" Odd said, before taking off. "Is it cool if I go with Yumi?" Casey asked Ulrich. "If it's cool with Yumi that Karai comes with me," the brunette said.

"Go ahead," Yumi said, gesturing to the two. Karai joined Ulrich on his Overbike, while Casey did the same on the Overwing.

"Wait, what about William?" Karai asked. "I don't have a have a vehicle, so I guess I'll just

stay here and protect Aelita's back," he replied, turning back to the corridor that they came from.

As they passed a couple Manta Rays, the monsters started to spit out what looked like little skulls with X.A.N.A.'s symbol on them. "What are _those_?" Casey asked. "Mines," Yumi replied, veering the Overwing to avoid the small bombs.

Odd tried to do the same, but April got hit with one of the mines.

"April, you just lost 20 life points,' Jeremie warned. "Laser arrow!" Odd exclaimed as he fired, hitting one of the monsters, causing it to explode.

Aelita continued to gather all the turtles' particles, until she collected the last one for Mikey and transferred it to Jeremie's control panel, "Okay, Jeremie, I got all of them, you can take over."

"I'm on it, you help the others," Jeremie replied. Aelita sprouted her wings and jumped off the edge, flying over to the others.

Casey turned the dial on this hockey stick to the purple dot. He stomped his foot again, letting a puck of the same color fall out. "Okay, let's see what this one does," he said, slapping the disc with his stick.

It collided with the Manta Ray behind him and Yumi and it seemed to sink down, falling onto its own mines, exploding into digital bits.

"Good job, Casey," Jeremie said, "It looks like that weakened the monster."

A Manta fired a laser at April and she blocked it with her tessen. The gauge on it filled only an eighth of the way. "Odd, fly under the mines, I want to try something," she told him. Odd didn't understand her plan, but he did it anyway.

When they flew under the mines, April held up her weapon and it swept a few of the mines. Like before, it started to glow blue again. "Guys, try to gather all the Mantas in one place!" she called to the others.

Yumi and Casey got three monsters to follow them, while Ulrich and Karai got two more to follow them, and Aelita got one.

They all convened in one spot, creating a group of the flying creatures. "I hope you have a real plan," Odd said, preparing to fire a laser arrow. "You bet," she said before throwing her weapon, which went through all six Mantas.

She caught it and it changed back to normal. "You'll have to tell me how that works," Yumi said, she and Casey flying over to them.

"Hey, Jeremie, how's the particle reassembling going?" Aelita asked.

"Almost done," he replied, "But I can't virtualize them in Sector 5, you'll have to go into a way tower in the mountain sector.

"Got it," Aelita said. "Hop on, William," Ulrich offered. William jumped behind Karai on the Overbike. The snake girl fell silent, not turning around to look at him.

"Okay, I'm opening the northern tunnel," Jeremie said. He hit a few keys and one of the tubes sticking out of the dome of Sector 5 disappeared. "Alright, everyone, hold on," Odd said as they all flew through the hole in the wall of the sector.

When they emerged, they all found themselves on a mountainous terrain. "Where are we?" Karai said. "The mountain sector," Aelita said as her pink wings disappeared. "Come on, we have to get to a way tower," Yumi said. "What's a way tower?" April asked.

"It's the way to get from one sector to another," Ulrich explained.

"There's one 21 degrees south of you," Jeremie told them.

"Let's go," April said. They took off toward the tower.

"So, what are these towers?" Casey asked. "X.A.N.A. uses them to launch an attack on Earth," Yumi explained. "He activates one and uses the power from that attack," Ulrich added. "The only way to stop him is to deactivate the tower and Aelita is the only one who can do that," Odd said. "He's gotten a lot stronger over the years, that's why we recruited William," Aelita said, "We discovered that using the Return to the Past function on the computer actually makes him stronger, so we try to avoid using it as much as we can."

"Is that the tower?" Karai said, pointing to the white structure.

They all stopped in front of the tower.

"Okay, Aelita just has to go into the tower and finish the coding, and the turtles should virtualize in front of the tower," Jeremie said. His girlfriend ran into the tower, phasing through the wall.

After a few minutes, they all saw the three turtles start to form.

When they fully virtualized, they fell to the ground like everyone else, expect Donnie fell on his back, Raph fell on his stomach, and Mikey on his butt.

They groaned as they stood back up. "Guys!" April exclaimed, running up and hugging them. "What the heck happened?" Mikey asked aloud. "There was a _little_ problem with your virtualization process," Odd said. "What the heck is up with you guys?" Donnie asked, looking at all of them. "Yeah," Raph agreed, "Why does Odd look like a giant, purple cat?"

"They're our Lyoko avatars," Yumi said, "It's how we fight X.A.N.A."

"Is that why April looks like a hippie psychic?" Mikey asked. "Yes," Aelita said, walking out of the tower, "When you get transferred to Lyoko, you're given a different form. We can't fight X.A.N.A. in our normal clothes. You guys are different, too."

The brothers looked at each other and noticed their difference.

Their back shells were now metallic and color-coordinated to their usual masks. Their weapons were sheathed in their normal places. On their tan knee pads were Japanese characters in their colors. Donnie had the Chie character (character for wisdom.) Raph had the Chikara character (character for strength.) Finally, Mikey had the Kōi character (character for act (I used that because I couldn't find a shorter character that would fit him.))

"I want to see," Leo said. "Hang on," Jeremie said, starting to type, "Aelita, can you give me a visual?"

"Sure." A window popped on the screen, showing what she was seeing. She focused her eyes on the turtles so they could see them. Leo looked at them, while Jeremie continued to work on disinfecting the scanners. "Whoa," Leo said, "Hey, looking good, guys."

Mikey looked around in confusion, "Leo? Dude, where are you?"

"He's still on Earth," Aelita said, "Right now, he's looking at you through me," Aelita said.

"So, this is where X.A.N.A. controls his attacks?" Donnie said, looking at the world around them. "Yep, X.A.N.A. basically controls all the life on Lyoko," Ulrich said. "Except us," Odd said. "Speak for yourself," William said with a cocky smile. "That's right," Donnie said, "You said you got possessed."

"So, how do you stop him?" Raph asked. "When X.A.N.A. attacks, he activates one of those towers," Odd said, pointing back to the tower that Aelita came out of. "From there, it's our job to safely get Aelita to the tower because she's the only one that can deactivate it," Yumi explained. "Alright, how can you tell if it's activated or not?" Mikey asked.

"Well, you see how that tower's glowing white?" Ulrich pointed out, "Activated towers glow red. Plus, when X.A.N.A.'s awake, his attack causes pulsations in the ground that lead to the tower."

"That's how I could tell when there was an attack before I left Lyoko," Aelita told them. "Doesn't sounds that hard to stop an attack," Raph said. "Oh, it wouldn't be," Odd said, "If it wasn't for X.A.N.A.'s little minions."

"Little minions?" Raph asked.

Again, the charm on April's necklace glowed again, "Speak of the devil," she said, looking over and saw five short, tan creatures that ran on four metallic legs each. "Kankrelats?" Odd scoffed, jumping back on his Overboard, "This is gonna be easy."

"They don't look that threatening," Raph said. "No kidding," Casey said. He ran toward them, until one of them fired a laser at him, to which he put his arms together, causing his shield to appear before him. "Whoa! Dude, how'd you do that?" Mikey asked astonished. Casey just smiled at him, before he pulled his stick out and switched the dial back to red, "If you think _that's_ cool, check this out."

He stomped his foot and let a red puck fall out. "What is that?" Donnie asked. "Check it," Casey replied before slapping it, hitting a monster.

The Kankrelat burst into flames then exploded into particles like the other monsters. Another Kankrelat fired a laser, which missed Raph. "Did that bug just shoot at me?!" Raph exclaimed. He ran toward it, pulling out a metallic sai and threw it at the monster, hitting it directly in the center of its symbol.

It exploded into bits and Raph pumped his fist in the air.

One of the other Kankrelats fired a laser and hit April in the chest. The blast made her kneel down as sparks appeared in the spot she was hit. "April!" Donnie said, coming over and kneeling next to her, "Are you okay?"

"I'm fine," she said, standing back up quickly, "It didn't even hurt, just surprised me." She blocked five lasers with her tessen, until its gauge was full and it was glowing again. "Why is your tessen glowing?" Donnie asked. "Watch," April simply said, throwing the weapon, taking out the remaining monsters.

A cube-shaped creature came up behind Karai and hit her with a laser that froze her in her spot.

"Karai!" the turtles, April and Casey exclaimed when they saw her freeze. "Laser arrow!" Odd said, firing his arrow, destroying the monster.

"Is she okay?" Leo asked Jeremie. "The attack just took out the rest of Karai's life points," Jeremie said, checking her avatar card. "What does that mean?" Leo asked. "She's out of the game," Jeremie said.

When the ice finally broke, Karai turned into pixels, until she disappeared completely. "No!" Mikey cried out. "Guys, calm down," Yumi said, trying to relax them. "Jeremie, please tell me you got the scanners disinfected," Aelita said. "Just in time," Jeremie said, "Thank goodness."

+=0=+

The scanner door opened, with Karai falling out. She sat up and looked around, seeing the scanners. "I'm back?" she asked herself.

She held onto one of the scanners as she stood up, her legs feeling weak.

Once she was on her feet, she slowly made her way to the elevator, stumbling every few steps. She pressed the button and waited for the door to open.

When it finally opened, she stumbled in, grabbing onto the back wall and rested against it. She reached over and hit the button, then sunk to the floor.

+=0=+

Leo was worried when he saw Karai's avatar card disappear from the screen.

He looked over when he heard the elevator door open and saw his sister sitting on the ground. "Karai!" he said, running over and helping her up, "Are you okay?"

"I'll make it," she said. "She's just a little weak because she was just devirtualized for the first time," Jeremie said, "It takes a little while to get used to it."

"I think we should call it a day, Jeremie," Ulrich said, noticing that the turtles, April and Casey looked nervous. "Okay, I'll bring you in," Jeremie said.

"Uh, will there be any problem bringing us back?" Donnie asked. "There shouldn't be," the young genius replied, "But, just in case, I'll bring you guys back last."

They watched as their friends disappeared into pixels, one by one as Jeremie called them back.

Finally, it came down to the three of them, standing alone in the virtual world.

"What if it messes up again?" Karai asked. "I embedded the debugging program into a separate materialization program for them," he replied. He took a deep breath and finally put his hands back on the keyboard, "Well, here goes nothing."

He began typing away again, "Materialization, Donnie. Materialization, Mikey. Materialization, Raph."

The seven teens waited patiently by the scanners as they whirled to life.

Yumi had her fingers crossed in front of her, before the scanners opened and the three turtles fell out. "Guys!" April exclaimed as they started to climb back to their feet. "Dudes, are you okay?" Casey asked, helping Raph up. "I think so," he said, holding his head. "Apart from what happened to Karai," Mikey said somberly.

Aelita giggled, "How about we take you to the lab so Jeremie can figure out what happened?"

April, Casey, and William helped the turtles to the elevator and they all got in as soon as it arrived.

+=0=+

 **A/N: Thank you all for reading! I hope you like the turtles' Lyoko forms. I _was_ going to make them look like they did in their 2003, season six series, _Fast Forward,_ but I didn't know how I would've described it, so I went with the somewhat simple form in this chapter. Speaking of Lyoko forms, a few chapters ago, I wanted to see if anyone knew who I got the idea for April's form from. I want to tell you that no one ever took a guess, so I'll tell you that I got the idea from Maya Fey, from the video game/anime Phoenix Wright: Ace Attorney. I felt inspired to use her because she is a psychic medium. Please let me know what you think in the reviews what you think of their forms. Thank you for reading and following and I'll see you all in the next chapter! MEOW!**

 **-Kittenclysm**


	14. Brand New Team

**A/N: Hello, my kitties! I'm back with another chapter of Code: Mutation! I don't know if this would be considered late, but it just felt like it took me a long time to write. Plus, I don't feel like there's much content to it. It's just because I'm starting to get into watching anime and reading manga. I've been reading _To Love Ru_ and watching _Death Note._ Not to mention, I'm going to attempt to write my own manga. Plus I've got a few other anime lined up to watch. But I am going to continue to work on my fanfictions. It's one of my favorite things to do! Anyway, let's get going!**

 **Disclaimer: I own nothing!**

+=0=+

Chapter 14)Brand New Team

The three teens helped their turtle friends out of the elevator, each one of them looking depressed. "What's wrong with you guys?" Jeremie asked, noticing their sadness, "Why are you so down?"

"Are you joking?!" Raph said angrily, "We just saw our sister get killed in you STUPID virtual world!"

"Raph, listen..." Ulrich started. "No, YOU guys listen!" Donnie interrupted, "I'm pretty sure you know that world is dangerous, but you risked _our_ lives for your own need! Well, we're not going to be pawns in this sick program! We want out!"

"Guys!" Karai exclaimed. "WHAT?!" the three angrily shouted at her, causing her to step back in shock.

It took them a few seconds until they registered who they were yelling at. "K-Karai?" Mikey said softly, "Is that really you?"

"Who else would it be?" she said with a smirk. "But how?" Raph asked, "We all saw you get iced on Lyoko."

"That's what we were going to tell you," Yumi said, "When we lose all of our life points on Lyoko, we just get sent back here to Earth."

"It's kind of like a video game," Odd said. "Sort of like a virtual reality game," Donnie said. "Except that there is a minor chance that something can go wrong and you may not come back," Aelita said. "Yeah, like if you fall into the digital sea," Casey said.

"I still want to know what went wrong during the turtles' transfer," Yumi said. "I'm pretty sure their mutation infected the scanners," Jeremie said, typing on the computer. "But that doesn't make sense," April said, "Karai's technically a mutant, too. So shouldn't she have been the one that infected the scanner?"

"That's what I'm trying to figure out," Jeremie said, looking at the computer. "Well, how does the transfer process work?" Karai asked. "Well, it works by scanning the person's human DNA and copying it into the Lyoko database, and then transfers the data into their avatar," Jeremie said. "That's it!" April said. "What's it?" Casey asked. "Karai was born human, so she has human DNA," April explained, "But the turtles were born turtles, which means they have any to copy. That's why the scanners got infected and they didn't make it to Lyoko on the first try."

"That makes sense," Jeremie said.

"Hey, can we go? It's almost lunchtime!" Odd whined, "Plus, I have to walk Kiwi."

"Kiwi?" Karai asked. "Oh, yeah, you never saw him," Ulrich said. "Wait, does Kiwi have anything to do with the barking I heard in your room this morning?" Casey asked. "Uh, yeah, Kiwi's my dog," Odd said. "Dog?" April asked, "I thought pets weren't allowed on school grounds."

"He's not, that's why we keep him a secret," Ulrich said. "Yeah, and now that you're part of the team, you have to keep him a secret, too," Yumi said.

"Sure," Karai said. "Why don't we go eat and we can walk him together?" April asked. "Okay," Odd said, "Let's go!"

They all started to walk to the elevator, until the turtles noticed that Donnie and Jeremie were still by the computer. "Hey, you guys coming?" Leo asked.

"You guys can go ahead," Jeremie said. "Yeah, I'm gonna stay here so Jeremie can show me some of the functions on the supercomputer," Donnie said.

"Does this mean I can have your lunch?" Odd asked. "Yeah, go ahead," Jeremie said, waving his hand.

"'kay, see you guys later," Mikey said as he followed the other ten to the elevator. They all piled in and the door closed, heading back to the surface.

+=0=+

 **A/N: Thanks for reading and please remember to read, review, and share. Remember to leave me ideas and I'll see what I can do. I'll see you in the next chapter! MEOW!**

 **-Kittenclysm**


	15. Debugged

**A/N: Hello, my kitties! Welcome back to Code: Mutation! I like to greet my newest followers, Kpmariopokemonsonicfan, Lord Revan Reborn and Maximum Rhapsody. Welcome to the group. Just so everyone knows, this chapter contains something I thought of before I started the story that has been foreshadowed in a couple chapters. It's kinda a cutesy thing. You'll see what I mean. ;) Anyway, let's get on with the story!**

 **Disclaimer: I own nothing!**

+=0=+

Chapter 15)Debugged

Jeremie typed away on his computer as his roommate walked in and dropped on his bed. "Hey, Casey," he said, not looking away from the screen, "How was your training?"

"Exhausting," he said into his pillow, but strained to sit up, "I just don't understand the point of memorizing all of these stances before actually learning the attacks."

"Didn't April and Karai have to learn the same things?" the blond asked. "That's the thing, they were taught different ways. April was trained to honor the ninjutzu codes and Karai was trained to be a ruthless assassin. She's trying to dial it down for my training sessions, but she's still like a drill sergeant," he explained.

"Well, how did Yumi and Ulrich do?"

"You know them, they're way ahead of me when it comes to physical training. They're picking it up quick." It was then that Casey noticed the multiple panels on Jeremie's computer.

One had a diagram of one of the turtles in a T-pose, connected to another panel full of code and one DNA helix. The other was a diagram of something that he had no clue of what it looked like. "Hey, what's are you doing on your computer?" he asked. "A couple things," Jeremie said, turning back, "For one, I'm trying to fix the bug in the turtles' code before I try sending them back there."

"Yeah, you still have to scan Leo in," Casey pointed out, moving behind him to get a better look at the screen, "What the heck is that?" He pointed at the strange thing that he now thought slightly resembled a form of spaceship. "That is the Skidbladnir," the blond answered, "It's what we use to get into the internet."

"Kinda looks like a spaceship," Casey laughed. "Close," Jeremie said, "It's more like a submarine. It's one of the few things that can survive in the digital sea. I'm trying to add more docking pods to the ship so you guys can travel with them."

"Why do you need to go into the digital sea?" Casey asked, slightly confused. "Remember how I said that we found a way into the internet? Well, the entrance is located in the digital sea," Jeremie explained, suddenly going back to the turtle diagram, "But let me see if I got this bug fixed first."

He pressed the ENTER key on his keyboard and the diagram started to disappear, until a red exclamation mark appeared on the screen. "Dang it!" Jeremie exclaimed, slamming his hands on the desk. "Whoa, dude, relax," Casey said. "I'm alright," Jeremie said, "It's just that it was this way before I completed the materialization program and got Aelita out of Lyoko. It took me a couple years to finish that and I'm afraid that it's going to be near impossible to figure this out!"

"Well, what do you think is the problem?"

"I'm pretty sure it's because the supercomputer can't read their DNA through their mutation," Jeremie said, "If I had a sample of that mutagen that transformed them, I can probably work it into their own virtualization code."

"Hate to tell you this, but Donnie left all the mutagen in New York. He thought it might've been too dangerous to bring with us."

The two boys sat in silence for a moment, until an idea crossed Casey's mind, "Hey, do you think there's probably traces of mutagen in their skin or something that you can analyze or something?"

Jeremie looked at his roommate incredulously. "I can't believe I didn't think of that!" he said. He ran back to his computer, "There might be something in the code."

After a minute of searching, he sighed in defeat. "What's up?" Casey asked him. "The scan of their DNA is still bugged," Jeremie replied, "Their avatars are still there, but the computer still can't clearly read the mutation. It's probably because they've been mutated for 16 years."

"So, what do we do?"

"I might be able to crack this if I had a sample of a more recent mutation."

"Like Karai?" Casey asked. "That might work," Jeremie said, "If I get one of her scales, I think I can scan it and use it to fix the turtles' programs."

He grabbed a few of his things and turned to Casey, "You think you can get that for me and meet me at the factory?"

"Sure, I don't have anything else to do," Casey said with a shrug. He left the room with Jeremie and headed back to the gym.

+=0=+

April and Karai were in the gymnasium, folding up the mats they were using for their ninjutzu lesson with their friends. "It was nice for Jim to let us use this place," April said. "Yeah, it just sucks that we have to clean up," Karai said. "Well that was the deal we made with him," April pointed out. "Sure," Karai said, picking up a basketball laying on the ground. She threw it over her head, making the basket. The redhead picked it up and placed it on the racks with the others, "And you know, I think you could lay off Casey a little."

"How else is he supposed to learn?" the girl laughed, "I'll try."

April thought for a minute, then remembered something. "Hey, Karai, can I ask you something?" she asked. "Sure," Karai replied, "What's up?"

"Well, when X.A.N.A. first attacked, he tried attacking me, but he couldn't take control of me. He did infect my T-phone, so you lent me yours while Donnie was going to fix mine," April explained. "Yeah, and?" Karai said. "Well, I know it's not cool, but I snooped through it a little," April said. "Yeah?" Karai said, picking up a discarded dumbbell, looking at her friend. "I was just wondering...why is there a candid picture of William on there?"

Karai dropped the dumbbell, creating a loud bang as it hit the ground. "You, uh, you saw that?" Karai asked, seeming a little nervous, "You didn't tell anyone, did you?"

"No! I figured you didn't want anyone to know," April said defensively, "So what's up with the picture?"

Karai kept her back turned to April, not saying a word, but the psychic could still see through her silence, "Wait, do you...like him?"

With her face hidden, April couldn't see the blush creep across Karai's face. "W-what if I do?" she said, continuing to clean. April let out a little scoff at Karai's comment, "Are you ashamed of a little crush?"

"Can you blame me? I was raised to think that having those kind of feelings would only make me weak," Karai said, then hung her head, "I just never knew it felt like this."

April folded up another mat. "You know Shredder's wrong, right?" she said, "I mean, Splinter loved your mom, the turtles..." She walked over to Karai and placed a hand on her shoulder, "...Even you." Karai let out a little chuckle, "Leo said something like that before we left New York."

"Then why don't you take a chance?"

Karai finally turned around and smiled, "I guess it's worth a shot."

The door to the gym opened, with Casey coming in, "Hey, guys."

"Hey, Casey. Sorry about being so tough on you during training," Karai said. "Eh, no problem," he replied, "But there _is_ something I need from you."

"Okay," she said, "What is it?"

"Well, Jeremie thinks that if he had something with a trace of mutagen on it, he can probably fix the turtles' programs and they can get back to Lyoko," he explained, "And since _you_ were the most recent mutated person we know, he thought that he could use one of your scales."

"Uh, I guess that'd be okay," Karai said. She shifted her hand into snake form and Casey pulled out one of the scales. "Alright, I'm gonna go take this to Jeremie," Casey said, slipping the scale in his pocket and heading to the door, "See you guys later."

+=0=+

Jeremie and Casey ran and slid down the ropes, landing in front of the elevator and seeing the turtles off to the side. "Hey, guys," Leo greeted. "Did you figure out the debug program yet?" Donnie asked. "Not exactly," he replied, "But I think I almost got it."

They all got into the elevator and went to the lab.

"So, how did you figure it out?" Raph asked. They were in the lab, gathered around the computer. "Actually, Casey suggested it and I figured it wouldn't hurt to try it," Jeremie said. "Wait, Casey had an idea?" Donnie said jokingly. "Yeah, I was surprised, too," Jeremie laughed.

"So, how are you doing it?" Leo asked, "I can't wait to go to Lyoko!"

"With this," Casey said, pulling out the scale. "Is that one of Karai's scales?" Mikey asked. "Yep. Casey, go put that in one of the scanners," Jeremie ordered. "On it," said Casey, getting into the elevator. "So, what is Karai's scale going to do?" Donnie asked. "Well, I figured that the reason that the scanners malfunctioned when you were scanned was because it couldn't read the human DNA you got from your mutation because of the mutagen that caused it. But if I'm able to get the code from the mutagen that's embedded into Karai's scale, I can use it to hopefully clean up your scans, so you can travel to and from Lyoko like the others.

Casey came out of the elevator, "Okay, it's in the scanner."

"Good," Jeremie said. He turned back to the computer and began typing.

A diagram of the scale appeared on the screen as it was being scanned. "Now I just need to extract Karai's DNA sequence," he said. A second window opened, full of multiple lines of codes. "You can seriously understand all of this?" Raph asked. "It's not that difficult when you've worked on it as long as I have," Jeremie replied.

The scan of Karai's scale disappeared, leaving a sequence of strange symbols. "That's strange," Jeremie said, "I don't recognize this at all."

Donnie looked at the screen, "That's because it's written in Kraang."

"Okay, so I was _close_ to fixing it," Jeremie said. "Well, I can decode it," Donnie said. "You can?" Jeremie said. "Sure, no problem," answered the genius mutant, "It'll probably take a couple days with my laptop."

"Well, if it'll help, you can use the supercomputer," Jeremie offered, "As long as you don't mess with my codes."

"That could work," Donnie said. "Then you can take the wheel," Jeremie got out of the chair, letting Donnie in his place. "Well, we're gonna go get some dinner," Casey said. "Yeah, before Odd gets to it," Jeremie said. The two boys left the turtles in the lab, until Leo, Raph, and Mikey decided to leave Donnie on his own to work.

+=0=+

 **A/N: I hope you all like my choice for a relationship. Like I said, I thought about it before I even published the story. I know it'd be a little weird, but I think it's time that Karai actually have feelings for someone. Also, all the computer stuff that I wrote in the chapter about getting their scans fixed is all off the top of my head. I'm not really that sure about most of that stuff. I just thought it would make a little sense. Anyway, please R, R, & S. And, if you want, please lend me any ideas you have. I'll see you in the next chapter! MEOW!**

 **-Kittenclysm**


	16. Short Trip

**A/N: Hello, my kitties! Welcome back to Code: Mutation. I'd like to welcome my newest follower, Spyro259. I hope you're enjoying the story so far and continue to enjoy. Sorry this took so long, I just haven't been feeling up to it. Let's go ahead and get going!**

 **Disclaimer: I don't own either show, characters or anything!**

+=0=+

Chapter 16)Short Trip

Jeremie walked out of the elevator, only to find Donnie, asleep in the chair.

"Donnie, wake up," he said, nudging the turtle. Donnie stirred a little, but remained sleeping. "Donnie!" Jeremie said louder. Donnie awoke with a jerk and looked around for a second, remembering his surroundings. "Oh, hey, Jeremie," he said, "Shouldn't you be in class?"

"It's 3 o'clock," the blond replied, "How long have you been working on that code?"

"All night, but I think I got it figured out," he typed on the computer, pulling up the turtle diagram. He pressed a few keys and the turtle drained away, then turned into a green plus sign. "Donnie, you did it!" Jeremie exclaimed, "I'll call the others." He pulled out his phone and dialed Aelita's phone.

+=0=+

In minutes, everyone was gathered in the lab, ready to return to the digital world. "So, you fixed the virtualization program?" Leo asked excitedly. "Yep, now the four of us can safely go to and from Lyoko," Donnie said. "Does it work?" William asked. "Well, it got a positive reaction when Donnie tested it," Jeremie said. "Okay, so how about we do the same thing last time and have _us_ go in first, just in case something goes wrong again?" Yumi asked. "Sounds good to me," Aelita said, "Any objections?"

Everyone shook their heads, agreeing with the guardian. "Okay, head down to the scanners and I start the process," Jeremie said, turning to the computer. "You got it," Raph said, everyone readying themselves.

+=0=+

 _"You guys ready to try this again?"_ Jeremie asked the turtles once everyone else was sent to Lyoko. "Can't hurt to try," Mikey said. "Hopefully," Raph stated. "I'm sure everything will go right this time," Donnie said. The three got back in the scanners, which closed on them.

 _"Transfer, Donnie, transfer, Raph, transfer, Mikey,"_ Jeremie read off, _"Scanner. Virtualization."_

The scanners opened up, the three brothers gone. "Jeremie, how'd it go? Are they there?" Leo asked.

"Hang on," Jeremie said, checking the turtles' avatar cards, which fully appeared on screen, "Guys? Did the turtles make it?"

"We're here, Jeremie," Donnie said. Everyone was standing the ice sector. "And it looks like everything's in place," Raph said, looking himself over. "Alright, you ready, Leo?" Jeremie asked.

"I guess," Leo said. He took a deep breath, stepped into the scanner and closed his eyes.

"Okay, here we go," Jeremie said, beginning to type, "Transfer, Leo. Scanner, Leo. Virtualization."

When Leo opened his eyes, he was in mid air, quickly falling to the icy ground, but landing on his feet. He stood up and looked around, seeing that they were standing on a white plateau, surrounded by seemingly endless, dark-blue water. He then look down at himself. He looked like his brothers, except for his blue armor shell and his knee pads had a blue Namari character (character for lead) on them. "Looking good, bro!" Mikey said. "Thanks," Leo said, then looked at everyone else, "Why do you all look like this?"

"To fight X.A.N.A.'s monsters," Odd said. "The supercomputer creates avatars for anyone scanned into it that gives them weapons and abilities to defend themselves here," Aelita explained. "Well, some of us have abilities," William said, crossing his arms. "You don't have any?" Raph asked. "Well, I had 'super smoke' and I could use my weapon to fly when I was under X.A.N.A.'s control, but I can't figure out how to do it myself," he replied. "I have levitation," Yumi said. "I have super speed, triangulate, and triplicate," Ulrich said. "What about you, Odd?" Leo asked. "Well, I used to be able to see the future, but I lost that power and Jeremie thinks it's too dangerous to give it back to me," he explained. "What about you?" Mikey asked, looking at his friends. "I don't think I have any," Karai said. "I can do this," Casey said. He put his arms together in front of him, creating his shield, "But that's all I know about."

"What about April?" Donnie asked. "I think she has some kind of special ability that she can sense X.A.N.A.'s monsters before Jeremie can see them onscreen," Yumi said. "How do you know that?" Ulrich asked. "I noticed her Magatama glows right before a monster attacks," she replied. "Her what?" Odd asked. "Magatama, the charm on her necklace," Yumi said, pointing at the gold object.

After she did this, the Magatama began to glow. "Uh-oh," William said.

They pulled out their weapons and got into defense position. "Jeremie, do you see anything?" Ulrich asked. "No, I can only see you guys," Jeremie said, then growled, "X.A.N.A. must've jammed my tracker!"

"There!" April said, pointing to the sky.

Several wasp-looking creatures flew toward them. When they got closer, they began firing lasers out of their stingers.

Raph held up a sai, which reflected the laser back at one of the hornets, causing it to explode. "Awesome!" he said. From behind a group of Bloks came at them. "What the heck is going on here?" Karai said as she was hit in the back with a laser. "This usually only happens when X.A.N.A. is on the attack," Yumi replied.

"What is _that_ thing?" April said, seemingly afraid as the charm glowed again. She started to back up, until she was at the edge of the plateau, nearly falling off. "April, what's wrong?" Leo asked, not getting a reply as the girl seemed to stare at something invisible in front of her.

Then her stare became blank as her body started to lift off the ground. "April!" Donnie called, only for April to be stuck.

" _Guys, it's the Scyphozoa,_ " Jeremie told them. "It's invisible?" Raph asked aloud.

"It's probably trying to take control," Aelita said, "Odd, shoot it!"

"Laser arrow!" he exclaimed as he fired at the invisible creature. When it made contact with it, a large, jellyfish-like creature appeared. April's eyes opened wide as she was finally released and dropped on the ground. "April!" Donnie yelled, running over to his friend as they finished off the swarm of monsters.

" _April, you just lost 80 lifepoints in one attack!_ " Jeremie said. The girl slowly rose to her feet with Donnie's help and held a hand to her head, "Guys, I feel weird."

"Jeremie, I think that's enough for today," Leo said. "Oh, man," Mikey whined slightly, only to disappear into pixels seconds later with the others.

+=0=+

April was the last to be brought back from Lyoko. She nearly passed out coming out of the scanner, luckily caught by Donnie and Raph. "April, are you alright?" William asked, worriedly. "I'm not sure," she replied, "I still feel really weird."

" _You guys might want to come up here_ ," Jeremie said. They got in the elevator and went to the lab.

"What's up, Einstein?" Odd asked as they exited. "I did a scan on April as she was being materialized and I think I figured out what the Scyphozoa did to her," Jeremie replied. "What?" Donnie asked. "Take a look," he replied, moving away from the computer so the turtle could see.

"No way!" the purple-masked turtle exclaimed. "What?" April asked. "Well, this might sound strange, but X.A.N.A. took the Kraang side of you," he answered. "I don't believe it," April said weakly. She pulled out her phone and tried to move it telepathically, but it did nothing. "Are you saying that April is completely human now?" Leo asked. "That's right," Jeremie said, "But I'm afraid that there might be something more to that." He got out of the chair and led them to the lift, "Come on, I need to test something."

+=0=+

The elevator opened, revealing the dark, empty room. They stepped out, setting the lights off. "Whoa, dude, where are we?" Mikey asked. "Oh, that's right, you don't remember being here," Ulrich said. "The mainframe? What're we doing here?" April asked. They took a few more steps in, triggering the machine to rise from the floor. "What is this?" Leo asked. "This is what keeps the supercomputer on," Yumi explained, "If this thing goes down, Lyoko goes down with it." Jeremie stepped closer to it as the panel with X.A.N.A.'s symbol opened and the lever came out.

Something in April made her feel uncomfortable as he reached for it. "Wait!" she yelled to him, "Are you sure about this?"

"Don't worry. I'm just going to shut it off for a few seconds to test something," he said. He pulled the lever and April grabbed her head before collapsing on the floor. "April!" the turtles said, all of them crowding around her and Jeremie switched the computer back on.

+=0=+

 **A/N: I hope you liked the chapter. You all know the protocol, please read, review and share and, well, you know the rest. I'll see you in the next chapter. MEOW!**


	17. Digitally Restrained

**A/N: Hello, my kitties! Welcome back to Code Mutation! Sorry it's been a little while, but I was having some writer's block and had a few family problems in the last few months. But I'm back to present the new chapter! I'd like to welcome my newest followers, vnscheze and Digi-BlueFox. Welcome and I hope you're enjoying the story. Let's go!**

 **Disclaimer: I don't own Code: Lyoko or TMNT**

+=0=+

Chapter 17)Digitally Restrained

"Well, her blood pressure's a little low, but her breathing and heartbeat seemed to have returned to normal," Donnie said, checking on an unconscious April. "April?" Leo shook her, "April, wake up."

She slowly opened her eyes a few seconds later, "W-what happened?" she asked, sitting up. "You passed out," Ulrich said. "I was afraid of that," Jeremie said, typing on the computer. "What?" asked Karai. "Remember how we told you that when they got me out of the computer, we tried shutting it down, but found that X.A.N.A. had connected me to him by stealing my memories of my life on Earth?" Aelita asked them. "Yeah, you said that your memories were like an important fragment that you couldn't live without, so if it was permanently lost, you would die," Leo said. "Well, the fragments that contain April's Kraang DNA is exactly like Aelita's memory fragments," Jeremie informed them. "You mean that April is connected to Lyoko like Aelita was?" Yumi asked. "I'm afraid so," Jeremie replied. "Oh, man," Odd said. April covered her face in worry and discouragement. "Don't worry too much about it, April," Yumi said, placing her hand on April's shoulder, "At least we know what the problem is this time. We just need to find your fragments."

"That's right," Jeremie said, typing away, "And I think we should start ASAP."

"Really? But I'm so hungry!" Odd whined. "Well, it _is_ almost dinnertime," William pointed out. "It is?" Yumi asked. She pulled out her phone and looked at the time, "Oh man! My parents are gonna kill me! I gotta go!"

She ran into the elevator as she dialed a number on her phone and hit the button. "Hiroki! Where are mom and dad?" she asked her brother as the door closed.

"Yeah, we should get to the cafeteria before Rosa notices that Odd hasn't grabbed his two helpings," Ulrich joked. "You can have mine, too," Jeremie said, "I'm staying here to try and track down those fragments."

"I'll help you," Donnie said, "We can probably get it done twice as fast."

"Sounds like a plan, Einsteins," Raph said as he joined everyone else in the lift. "Good luck, guys," Leo told them.

+=0=+

April solemnly poked at her food, a million thoughts running through her mind. "Don't worry, April," Odd said, "If there's one person you can rely on to help you with this kind of problem, it's Jeremie."

"It's true. I think the only person that knows more about Lyoko is my father," Aelita said. "What I don't understand is what .A. wants with your alien DNA," Casey said, "And why he didn't finish you off if that was all he wanted."

"There's another problem, too," Ulrich said. "What's that?" Odd said, a mouthful of food again. "If April's missing fragments is like when Aelita was missing hers, then there's a danger of her getting devirtualized forever," the brunette pointed out. "Oh man, I didn't even think of that," Aelita said. April moaned and covered her face again. "Come on, April, you'll probably feel better after a little sparring," Karai said. April sighed, "Alright."

The two girls got up and started to walk out. "Hey, wait up, guys," William called, "I think I'll join you." Karai's back straightened at this and she found herself unable to even speak or look in his direction. "That's cool," April stepped in, "Right, Karai?"

"Uh, s-sure," the girl stuttered. "Cool," William said, following the two girls out. "That was weird," Odd said.

+=0=+

Jeremie worked on the supercomputer, while Donnie worked from his laptop, which the blond had allowed him to connect so they could work together.

"So, where should we start looking?" Donnie asked. "Well, we found Aelita's fragments in Sector 5," Jeremie said, "Maybe we should check there first."

"What is Sector 5 anyway?" Donnie asked. "It's the source of all of Lyoko's codes. Basically it the inside of X.A.N.A. himself," Jeremie replied, "There's a terminal at the edge of the sector that Aelita can access that's full of information about Lyoko," Jeremie typed on his computer and the holographic map of Lyoko turned into Sector 5.

"Incredible," Donnie said, nearly slack-jawed at the image. "Right?" Jeremie said, "And there are a few other things in Sector 5, too."

"Like this?" Donnie asked, noticing the giant aquatic vessel on the screen. "Yeah, that's the Skidbladnir," Jeremie said, "The submarine we use to get into the internet. I've been trying to figure out how to have all of you to fit in it, too."

"Well, how's that going?"

"I can't figure out how to do it. I'm planning on expanding the Skid, but I'm not sure if I should make the pods large enough for two people or to add more pods."

"How about you send me the schematic for the Skidbladnir and maybe I can figure something out. "Really?" Jeremie asked. "Sure," Donnie said, "They don't call me 'Einstein' for no reason."

"Okay, I guess it couldn't hurt," Jeremie said. He typed a few things on his computer and the digital blueprints transferred on the turtle's laptop. "Cool," Donnie said. He saved the file and the two continued with their search, until an alert appeared on their computers. "What's that?" Donnie asked. Jeremie checked his computer and exclaimed, "Oh no!"

"What is it?"

"Go get your brothers. I'll call the everybody else. This is an emergency!" Jeremie ordered. "Alright," Donnie said, jumping up and running out.

+=0=+

 **A/N: Thank you all for reading. Remember to read, review, share and leave suggestions for what you would like me to put in and I'll try. And with the outbreak of COVID-19 (Coronavirus), I want to say to please stay indoors, wash your hands often and keep your distance and limit your contact with others as much as you can. If you see any early symptoms of the virus, make sure to get medical help immediately. We all need to do our part to stop this! Thank you and I'll see you all in the next chapter! MEOW!**

 **-Kittenclysm**


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